Cascade polymer complexes, process for their production and pharmaceutical agents containing said complexes

ABSTRACT

Cascade polymer complexes with at least 16 ions of an element of atomic numbers 20 to 29, 39, 42, 44 or 57-83, useful NMR or x-ray lymphography imaging.

[0001] The invention relates to new cascade polymer complexes, agentsthat contain these compounds, the use of the complexes in diagnosis andtherapy, and a process for the production of these compounds and agents.

[0002] The contrast media that are now used in clinical practice for themodern imaging processes of nuclear spin tomography (MRI) and computertomography (CT) [Magnevist®, Pro Hance®, Ultravist® and Omniscan ®] aredispersed in the entire extracellular space of the body (intravascularspace and interstitium). This dispersion space comprises about 20% ofthe volume of the body.

[0003] In clinical practice, extracellular MRI contrast media were firstused successfully in the diagnsis of cerebral and spinal diseaseprocesses since here a quite special situation exists with respect tothe regional dispersion space. In the brain and spinal cord,extracellular contrast media in healthy tissue do not leave theintravascular space because of the blood-brain barrier. In the case ofpathological processes with disruption of the blood-brain barrier (e.g.,malignant tumors, inflammations, demyelinating diseases, etc.), regionswith elevated blood-vessel permeability then develop inside the brainfor these extracellular contrast media (Schmiedl et al., MRI ofBlood-Brain Barrier Permeability in Astrocytic Gliomas: Blood-BrainBarrier Permeability in Astrocytic Gliomas: Application of Small andLarge Molecular Weight Contrast Media, Magn. Reson. Med. 22: 288, 1991).Affected tissue can be identified with high contrast relative to healthytissue by exploiting this disruption of vascular permeability.

[0004] Outside of the brain and the spinal cord, however, no suchpermeability barrier exists for the above-mentioned contrast media(Canty et al., First-Pass Entry of Nonionic Contrast Agent into theMyocardial Extravascular Space. Effects on Radiographic Estimate ofTransit Time and Blood Volume. Circulation 84: 2071, 1991). Thus, theconcentration of the contrast medium is no longer dependent on vascularpermeability, but only on the size of the extracellular space in thecorresponding tissue. Delimitation of the vessels relative to thesurrounding interstitial space using this contrast medium is notpossible.

[0005] A contrast medium that is dispersed exclusively in the vascularspace would be desirable, particularly for the visualization of vessels.The purpose of such a blood-pool agent is to make it possible, with theaid of nuclear spin tomography, to delimit tissue with sufficient bloodsupply from tissue with insufficient blood supply, and thus to diagnosean ischemia. Infarcted tissue can also be delimited, based on itsanemia, from surrounding healthy or ischemic tissue if a vasal contrastmedium is used. This is of special importance if, e.g., the point is todistinguish a myocardial infarction from an ischemia.

[0006] To date, most of the patients in whom there is suspicion ofcardiovascular disease (this disease is the most frequent cause of deathin Western industrialized countries) have to undergo invasive diagnostictests. In angiography at present, diagnostic radiology with the aid ofiodine-containing contrast media is used in particular. These testssuffer from various drawbacks: they are associated with the risk ofradiation exposure, as well as with difficulties and stresses, whichtherefore particularly have the effect that the iodine-containingcontrast media, as compared with NMR contrast media, have to be used inmuch higher concentrations.

[0007] There is therefore a need for NMR contrast media which can markthe vascular space (blood-pool agents). These compounds are to bedistinguished by good compatibility and by high effectiveness (highincrease of signal intensity with MRI).

[0008] Thus far, the attempt to solve at least a part of this problem byusing complexing agents that are bound to macromolecules or biomoleculeshas been successful only to a limited extent.

[0009] Thus, for example, the number of paramagnetic centers in thecomplexes that are described in European Patent Applications No. 0 088695 and No. 0 150 844 is not sufficient for satisfactory imaging.

[0010] If the number of metal ions required is increased by repeatedintroduction of complexing units into a macromolecular biomolecule, thisis associated with an intolerable impairment of the affinity and/orspecificity of this biomolecule [J. Nucl. Med. 24, 1158 (1983)].

[0011] Macromolecules can generally be suitable as contrast media forangiography. But 24 hours after intravenous injection in rats,albumin-GdDTPA (Radiology 1987; 162: 205), e.g., shows a concentrationin the liver tissue that constitutes almost 30% of the dose. Inaddition, only 20% of the dose is eliminated in 24 hours.

[0012] The macromolecule polylysine-GdDTPA (European Patent Application,Publication No. 0 233 619) has also proved suitable as blood-pool agent.Because of production, however, this compound consists of a mixture ofmolecules of different sizes. In excretion tests in rats, it was shownthat this macromolecule is excreted unchanged by glomerular filtrationthrough the kidneys. Due to factors related to synthesis, however,polylysine-GdDTPA may also contain macromolecules that are so large thatthey cannot pass through the capillaries of the kidneys in the case ofglomerular filtration and thus remain in the body.

[0013] Also, macromolecular contrast media based on carbohydrates, e.g.,dextran, have been described (European Patent Application, PublicationNo. 0 326 226). The drawback of these compounds lies in the fact thatthe latter generally carry only about 5% of the signal-enhancingparamagnetic cation.

[0014] The polymers described in European Patent Application No. 0 430863 already represent a step toward blood-pool agents since they nolonger exhibit the size and molecular weight relative to heterogeneitythat are characteristic of the previously mentioned polymers. They leavesomething to be desired, however, as regards complete elimination,compatibility, and/or effectiveness.

[0015] The object was therefore to make available new diagnostic toolsparticularly to identify and locate vascular diseases that do not havethe above-mentioned drawbacks. This object is achieved by thisinvention.

[0016] It has been found that complexes which consist ofnitrogen-containing cascade polymers that are provided with complexingligands, at least 16 ions of an element of atomic numbers 20-29, 39, 42,44 or 57-83, and optionally cations of inorganic and/or organic bases,amino acids or amino acid amides, and which optionally contain acylatedamino groups are surprisingly very well suited for the production of NMRand x-ray diagnostic agents without exhibiting the mentioned drawbacks.

[0017] The complexing cascade polymers according to the invention can bedescribed by general formula I

A—{X—[Y—(Z—<W—K_(W)>_(Z))_(y)]_(x)}_(a)  (I),

[0018] in which

[0019] A stands for a nitrogen-containing cascade nucleus of basemultiplicity a,

[0020] X and Y, independently of one another, stand for a direct bond ora cascade reproduction unit of reproduction multiplicity x or y,

[0021] Z and W, independently of one another, stand for a cascadereproduction unit of reproduction multiplicity z or w,

[0022] K stands for the radical of a complexing agent,

[0023] a stands for numbers 2 to 12,

[0024] x, y, z and w, independently of one another, stand for numbers 1to 4,

[0025] provided that at least two reproduction units are different andthat

16≦a·x·y·z·w≦64

[0026] holds true for the product of the multiplicities. As cascadenucleus A, the following are suitable: nitrogen atom,

[0027] in which

[0028] m and n stand for numbers 1 to 10,

[0029] p stands for numbers 0 to 10,

[0030] U¹ stands for Q¹ or E,

[0031] U² stands for Q² or E with

[0032] E meaning the group

[0033] whereby

[0034] o stands for numbers 1 to 6,

[0035] Q¹ stands for a hydrogen atom or Q² and

[0036] Q² stands for a direct bond,

[0037] M stands for a C₃-C₁₀ alkylene chain which optionally isinterrupted by 1 to 3 oxygen atoms and/or optionally is substituted with1 to 2 oxo groups,

[0038] R^(o) stands for a branched or unbranched C₁-C₁₀ alkyl radical, anitro, amino, carboxylic acid group or for

[0039] whereby the number of Q² elements corresponds to basemultiplicity a.

[0040] The nitrogen atom, whose three bonds (base multiplicity a =3) ina first “inner layer” (generation 1) are occupied by three reproductionunits X or Y (if X stands for a direct bond) or Z (if X and Y in eachcase stand for a direct bond), represents the simplest case of a cascadenucleus; in other words: the three hydrogen atoms of the basic cascadestarter ammonia A(H)_(a)=NH₃ have been substituted by three reproductionunits X or Y or Z. In this case, the number of Q² elements contained incascade nucleus A represents base multiplicity a.

[0041] Reproduction units X, Y, Z and W contain —NQ¹Q² groups, in whichQ¹ means a hydrogen atom or Q² and Q² means a direct bond. The number ofQ² elements contained in the respective reproduction unit (e.g., X)corresponds to the reproduction multiplicity of this unit (e.g., x inthe case of X). The product of all multiplicities a·x·y·z·w indicatesthe number of complexing agent radicals K bound in the cascade polymers.The polymers according to the invention contain at least 16 and at most64 radicals K in the molecule, which in each case can bond one to amaximum of three (in the case of divalent ions), preferably one, ion ofan element of the above-mentioned atomic numbers.

[0042] The last generation, i.e., reproduction unit W bound tocomplexing agent radical K, is bound to K with NH groups (—NQ¹Q² with Q¹meaning a hydrogen atom and Q²=direct bond), while the precedingreproduction units can be linked together both by NHQ² groups (e.g., byacylation reactions) and by NQ²Q² groups (e.g., by alkylationreactions).

[0043] The cascade polymer complexes according to the invention exhibita maximum of 10 generations (i.e., more than just one of reproductionunits X, Y and Z can also be present in the molecule in each case), butpreferably 2 to 4 generations, in which at least two of the reproductionunits in the molecule are different.

[0044] As preferred cascade nuclei A, those are indicated which fallunder the above-mentioned general formulas if

[0045] m stands for numbers 1-3, especially preferably for number 1,

[0046] n stands for numbers 1-3, especially preferably for number 1,

[0047] o stands for number 1,

[0048] M stands for a —CH₂, —CO or —CH₂CO group and

[0049] R^(o) stands for a —CH₂NU¹U², CH₃ or NO₂ group.

[0050] As further preferred cascade starters A(H)_(a), there can belisted, e.g.:

[0051] (In the parentheses, base multiplicity a is indicated for thecase where subsequent mono- or disubstitution is used in building thenext generation) Tris (aminoethyl) amine (a = 6 or 3); tris(aminopropyl) amine (a = 6 or 3); diethylenetriamine (a = 5 or 3);triethylenetetramine (a = 6 or 4); tetraethylenepentamine (a = 7 or 5);1,3,5-tris (aminomethyl) benzene (a = 6 or 3); trimesic acid triamide (a= 6 or 3); 1,4,7-triazacyclononane (a = 3);1,4,7,10-tetraazacyclododecane (a = 4);1,4,7,10,13-pentaazacyclopentadecane (a = 5);1,4,8,11-tetraazacyclotetradecane (a = 4);1,4,7,10,13,16-hexaazacyclooctadecanef (a = 6);1,4,7,10,13,16,19,22,25,28-decaazacyclotriacontane (a = 10); tetrakis(aminomethyl) methane (a = 8 or 4); 1,1,1-tris (aminomethyl) ethane (a =6 or 3); tris (aminopropyl)-nitromethane (a = 6 or 3);2,4,6-triamino-1,3,5-triazine (a = 6 or 3);1,3,5,7-adamantanetetracarboxylic acid amide (a = 8 or 4);3,3′,5,5′-diphenylether-tetracarboxylic acid amide (a = 8 or 4);1,2-bis[phenoxyethane]-3′,3″,5′,5″-tetracarboxylic (a = 8 or 4); acidamide 1,4,7,10,13,16,21,24-octaazabicyclo[8.8.8]hexacosan (a = 6).

[0052] It can be pointed out that the definition as cascade nucleus Aand thus the separation of cascade nucleus and first reproduction unitcan be selected by purely formal means and thus independently of theactual synthesis of the desired cascade polymer complexes. Thus, e.g.,the tris(aminoethyl)amine used in Example 4 can be considered as cascadenucleus A itself (compare the general formula, indicated first for A,with m=n=p=1, U¹═E with o meaning number 1 and U¹═U²═Q²) but also as anitrogen atom (=cascade nucleus A), which as a first generation exhibitsthree reproduction units

[0053] (compare the definition of E).

[0054] Suitable cascade reproduction units X, Y, Z and W are,independently of one another,

[0055] E,

[0056] in which

[0057] U¹ stands for Q¹ or E,

[0058] U² stands for Q² or E with

[0059] E meaning the group

[0060] whereby

[0061] o stands for numbers 1 to 6,

[0062] Q¹ stands for a hydrogen atom or Q²,

[0063] Q² stands for a direct bond,

[0064] U³ stands for a C₁-C₂₀ alkylene chain, which optionally isinterrupted by 1 to 10 oxygen atoms and/or 1 to 2—N(CO)_(q)—R² radicals,1 to 2 phenylene radicals and/or 1 to 2 phenylenoxy radicals and/oroptionally is substituted by 1 to 2 oxo, thioxo, carboxy, C₁-C₅alkylcarboxy, C₁-C₅ alkoxy, hydroxy, C₁-C₅ alkyl groups, whereby

[0065] q stands for numbers 0 or 1 and

[0066] R² stands for a hydrogen atom, a methyl or an ethyl radical,which optionally is substituted with 1-2 hydroxy or 1 carboxy group(s),

[0067] L stands for a hydrogen atom or the group

[0068] V stands for methine group

[0069] if at the same time U⁴ means a direct bond or group M and U⁵ hasone of the meanings of U³ or

[0070] V stands for group

[0071] if at the same time U⁴ and U⁵ are identical and mean the directbond or group M.

[0072] Preferred cascade reproduction units X, Y, Z and W are those inwhich in the above-mentioned general formulas, radical U³ stands for—CO—, —COCH₂OCH₂CO—, —COCH₂, —CH₂CH₂—, —CONHC₆H₄—, —COCH₂CH₂CO—,—COCH₂—CH₂CH₂CO—, —COCH₂CH₂CH₂CH₂CO—, radical U⁴ stands for a directbond, for —CH₂CO—, radical U⁵ stands for a direct bond, for —(CH₂)₄—,—CH₂CO—, —CH(COOH)—, CH₂OCH₂CH₂—, —CH₂C₆H₄—, CH₂—C₆H₄OCH₂CH₂, radical Estands for a group

[0073] The following can be cited as examples of cascade reproductionunits X, Y, Z and W:

[0074] —CH₂CH₂NH—; —CH₂CH₂N<;

[0075] —COCH(NH—)(CH₂)₄NH—; —COCH(N<)(CH₂)₄N<;

[0076] —COCH₂OCH₂CON(CH₂CH₂NH—)₂; —COCH₂OCH₂CON(CH₂CH₂N<)₂;

[0077] —COCH₂N(CH₂CH₂NH—)₂; —COCH₂N(CH₂CH₂N<)₂;

[0078] —COCH₂NH—; —COCH₂N<;

[0079] —COCH₂CH₂CON(CH₂CH₂NH6—)₂; —COCH₂CH₂CON(CH₂CH₂N<)₂;

[0080] —COCH₂OCH₂CONH—C₆H₄—CH[CH₂CON(CH₂CH₂NH—)₂]₂;

[0081] —COCH₂CH₂CO—NH—C₆H₄—CH[CH₂CON(CH₂CH₂N<)₂]₂;

[0082] —COCH₂CH₂CO—NH—C₆H₄—CH[CH₂CON(CH₂CH₂NH<)₂]₂;

[0083] —COCH₂CH₂CO—NH—C₆H₄—CH[CH₂CON(CH₂CH₂N<)₂]₂;

[0084] —CONH—C₆H₄—CH[CH₂CON(CH₂CH₂NH—)₂]₂;

[0085] —CONH—C₆H₄—CH[CH₂CON(CH₂CH₂N<)₂]₂;

[0086] —COCH(NH—)CH(COOH)NH—; —COCH(N<)CH(COOH)N<;

[0087] Complexing agent radicals K include those of general formulas IAand IB:

[0088] in which

[0089] R¹, independently of one another, stand for a hydrogen atom or ametal ion equivalent of atomic numbers 20-29, 39, 42-44 or 57-83,

[0090] R² stands for a hydrogen atom, a methyl or an ethyl radical whichoptionally is substituted with 1-2 hydroxy or 1 carboxy group(s),

[0091] R³ stands for a

[0092] R⁴ stands for a straight-chain, branched, saturated orunsaturated C₁-C₃₀ alkyl chain, which optionally is interrupted by 1-10oxygen atoms, 1 phenylene group, 1 phenylenoxy group and/or optionallysubstituted by 1-5 hydroxy, 1-3 carboxy, 1-phenyl group(s),

[0093] R⁵ stands for a hydrogen atom or for R⁴,

[0094] U⁶ stands for a straight-chain, branched, saturated orunsaturated C₁-C₂₀ alkylene group optionally containing 1-5 imino, 1-3phenylene, 1-3 phenylenoxy, 1-3 phenylenimino, 1-5 amide, 1-2 hydrazide,1-5 carbonyl, 1-5 ethylenoxy, 1 urea, 1 thiourea, 1-2 carboxyalkylimino,1-2 ester groups; 1-10 oxygen, 1-5 sulfur and/or 1-5 nitrogen atom(s)and/or optionally substituted by 1-5 hydroxy, 1-2 mercapto, 1-5 oxo, 1-5thioxo, 1-3 carboxy, 1-5 carboxyalkyl, 1-5 ester and/or 1-3 aminogroup(s), whereby the phenylene groups that optionally can be containedcan be substituted by 1-2 carboxy, 1-2 sulfo or 1-2 hydroxy groups,

[0095] T stands for a —CO-α, —NHCO-α or —NHCS-α group, and

[0096] α stands for the bonding site to the terminal nitrogen atoms ofthe last generation, of reproduction unit W.

[0097] As preferred complexing agent radicals K, those can be mentionedin which in above-indicated formula IA, the C₁-C₂₀ and preferably C₁-C₁₂alkylene chain that stands for U⁶ contains the groups

[0098] —CH₂, —CH₂NHCO, —NHCOCH₂O, —NHCOCH₂O, —NHCOCH₂OC₆H₄, —N(CH₂CO₂H),

[0099] —NHCOCH₂C₆H₄, —NHCSNHC₆H₄, —CH₂OC₆H₄, —CH₂CH₂O and/or issubstituted by groups —COOH, —CH₂COOH.

[0100] As examples for U⁶, the following groups can be cited:

[0101] —CH₂—, —CH₂CH₂—, —CH₂CH₂CH₂—, —C₆H₄—, —C₆H₁₀—, —CH₂C₆H₅—,

[0102] —CH₂NHCOCH₂CH(CH₂CO₂H)—C₆H₄—,

[0103] —CH₂NHCOCH₂OCH₂—,

[0104] —CH₂NHCOCH₂C₆H₄—,

[0105] CH₂NHCSNH—C₆H₄—CH(CH₂COOH)CH₂—,

[0106] —CH₂OC₆H₄—N(CH₂COOH)CH₂—,

[0107] —CH₂NHCOCH₂O(CH₂CH₂O)₄—C₆H₄—,

[0108] —CH₂O—C₆H₄—,

[0109] —CH₂CH₂—O—CH₂CH₂—, —CH₂CH₂—O—CH₂CH₂—O—CH₂CH₂—,

[0110] As examples for R⁴, the following groups can be indicated:

[0111] —CH₃, —C₆H₅, —CH₂—COOH,

[0112] —CH₂—C₆H₅, —CH₂—O—(CH₂CH₂—O—)₆CH₃, —CH₂—OH

[0113] If the agent according to the invention is intended for use inNMR diagnosis, the central ion of the complex salt must be paramagnetic.These are especially the divalent and trivalent ions of the elements ofatomic numbers 21-29, 42, 44, and 58-70. suitable ions are, for examplethe chromium(III), iron(II), cobalt(II), nickel(II), copper(II),praseodymium(III), neodymium (III), samarium (III), and ytterbium (III)ions. Because of their very strong magnetic moment, the gadolinium(III),terbium(III), dysprosium(III), holmium(III), erbium(III), manganese(II),and iron(III) ions are especially preferred.

[0114] If the agent according to the invention is intended for use indiagnostic radiology, the central ion has to be derived from an elementof higher atomic number in order to achieve sufficient absorption of thex rays. It has been found that for this purpose, diagnostic agents whichcontain a physiologically compatible complex salt with central ions ofelements of atomic numbers between 21-29, 39, 42, 44, 57-83 aresuitable; these are, for example, the lanthanum(III) ion and theabove-mentioned ions of the lanthamide series.

[0115] The cascade polymer complexes according to the invention containat least 16 ions of an element of the above-mentioned atomic numbers.

[0116] The remaining acid hydrogen atoms, i.e., those which were notsubstituted by the central ion, optionally can be replaced completely orpartially by cations of inorganic and/or organic bases, amino acids, oramino acid amides.

[0117] Suitable inorganic cations are, for example, the lithium ion, thepotassium ion, the calcium ion, the magnesium ion, and especially thesodium ion. Suitable cations of organic bases are, i.a., those ofprimary, secondary, or tertiary amines, such as, for example,ethanolamine, diethanolamine, morpholine, glucamine,N,N-dimethylglucamine, and especially N-methylglucamine. Suitablecations of amino acids are, for example, those of lysine, arginine, andornithine, as well as the amides of otherwise acidic or neutral aminoacids.

[0118] The compounds according to the invention, which have a molecularweight of 10,000-80,000 D, preferably 15,000-40,000 D, exhibit thedesired properties described above. They contain the large number,required for their use, of metal ions bound in a stable manner in thecomplex.

[0119] They accumulate in regions with high vascular permeability, suchas, e.g., in tumors, they make it possible to make observationsregarding the perfusion of tissues, and they provide the possibility ofdetermining the blood volume in tissues, of shortening selectively therelaxation times or densities of the blood, and of graphicallyrepresenting the permeability of blood vessels. Such physiological datacannot be obtained through the use of extracellular contrast media, suchas, e.g., Gd-DTPA [Magnevist®]. From these standpoints, there alsofollow the uses in the modern imaging processes of nuclear spintomography and computer tomography: more specific diagnoses of malignanttumors, early therapy monitoring in cases where cytostatic,antiphlogistic, or vasodilative therapy is used, early identification ofunderperfused regions (e.g., in the myocardium), angiography in vasculardiseases, and identification and diagnosis of (sterile or infectious)inflammations.

[0120] The cascade polymer complexes according to the invention are alsoextremely well suited for (interstitial and i.v.) lymphography.

[0121] As further advantages relative to extracellular contrast media,such as, e.g., Gd-DTPA [Magnevist®], the greater effectiveness ascontrast media for nuclear spin tomography (higher relaxivity) must beemphasized; this ensures a marked reduction of the diagnosticallyrequired dose. At the same time, the contrast media according to theinvention can be formulated as solutions in an isoosmolar manner in theblood and thus reduce the osmotic stress of the body, which is reflectedin a reduced toxicity on the part of the substance (higher toxicthreshold). Smaller doses and higher toxic thresholds result in asignificant increase of the reliability of contrast medium use in modernimaging processes.

[0122] In comparison with macromolecular contrast media based oncarbohydrates, e.g., dextran (European Patent Application, PublicationNo. 0 326 226), which carry—as mentioned—generally only about 5% of thesignal-enhancing paramagnetic cation, the polymer complexes according tothe invention exhibit a content of the paramagnetic cation of generallyabout 20%, although this figure is not intended to be necessarilylimiting. Thus, the macromolecules according to the invention producemuch better signal enhancement per molecule, which simultaneously hasthe effect that the dose necessary for nuclear spin tomography isconsiderably smaller relative to macromolecular contrast media based oncarbohydrates.

[0123] With the polymer complexes according to the invention, it hasbeen possible to design and produce macromolecules in such a way thatthe latter have a uniformly defined molecular weight. It is thuspossible, surprisingly enough, to control the size of the macromoleculesin such a way that the latter are large enough to be able to leave thevascular space only slowly, but at the same time small enough to be ableto pass through the capillaries of the kidneys, which are 300-800 Å insize.

[0124] In comparison to the other mentioned polymer compounds of theprior art, the cascade polymer complexes according to the invention aredistinguished by improved excretion behavior, greater effectiveness,greater stability, and/or better compatibility.

[0125] Another advantage of this invention lies in the fact that nowcomplexes with hydrophilic or lipophilic, macrocyclic or open-chain,low-molecular weight, or high-molecular weight ligands have becomeaccessible. As a result, the possibility exists for controlling thecompatibility and pharmacokinetics of these polymer complexes bychemical substitution.

[0126] The production of the cascade polymer complexes according to theinvention takes place in that compounds of general formula I′

A—{X—[Y—(Z—<W-β_(W)>_(z))_(y)]_(x) }a  (I′),

[0127] in which

[0128] A stands for a nitrogen-containing cascade nucleus of basemultiplicity a,

[0129] X and Y, independently of one another, stand for a direct bond ora cascade reproduction unit of reproduction multiplicity x or y,

[0130] Z and W, independently of one another, stand for a cascadereproduction unit of reproduction multiplicity z or w, a stands fornumbers 2 to 12,

[0131] x, y, z and w, independently of one another, stand for numbers 1to 4 and

[0132] β stands for the bonding site of the terminal NH groups of thelast generation, of reproduction unit W provided that at least tworeproduction units are different, and that for the product ofmultiplicities,

16≦a·x·y·z·w≦64,

16≦a·x·y·z·w≦64,

[0133] holds true,

[0134] are reacted with a complex or complexing agent K′ of generalformula I′A or I′B

[0135] whereby

[0136] R^(1′), independently of one another, stand for a hydrogen atom,a metal ion equivalent of atomic numbers 20-29, 39, 42-44, or 57-83 oran acid protective group,

[0137] R² stands for a hydrogen atom, a methyl or an ethyl radical whichoptionally is substituted with 1-2 hydroxy or 1 carboxy group(s),

[0138] R^(3′) stands for a

[0139] R⁴ stands for a straight-chain, branched, saturated orunsaturated C₁-C₃₀ alkyl chain, which optionally is interrupted by 1-10oxygen atoms, 1 phenylene group, 1 phenylenoxy group and/or optionallysubstituted by 1-5 hydroxy, 1-3 carboxy, 1-phenyl group(s),

[0140] R⁵ stands for a hydrogen atom or for R⁴,

[0141] U⁶ stands for a straight-chain, branched, saturated orunsaturated C₁-C₂₀ alkylene group optionally containing 1-5 imino, 1-3phenylene, 1-3 phenylenoxy, 1-3 phenylenimino, 1-5 amide, 1-2 hydrazide,1-5 carbonyl, 1-5 ethylenoxy, 1 urea, 1 thiourea, 1-2 carboxyalkylimino,1-2 ester groups; 1-10 oxygen, 1-5 sulfur and/or 1-5 nitrogen atom(s)and/or optionally substituted by 1-5 hydroxy, 1-2 mercapto, 1-5 oxo, 1-5thioxo, 1-3 carboxy, 1-5 carboxyalkyl, 1-5 ester and/or 1-3 aminogroup(s), whereby the phenylene groups that are optionally contained canbe substituted by 1-2 carboxy, 1-2 sulfo or 1-2 hydroxy groups,

[0142] T′ stands for a —C*O, —COOH, —N═C═O or —N═C═S group, and

[0143] C*O stands for an activated carboxyl group,

[0144] provided that—if K′ stands for a complex—at least two (in thecase of divalent metals) or three (in the case of trivalent metals) ofsubstituents R¹ stand for a metal ion equivalent of the above-mentionedelements and that optionally other carboxyl groups are present in theform of their salts with inorganic and/or organic bases, amino acids oramino acid amides,

[0145] are reacted, optionally present protective groups are cleaved,the thus obtained cascade polymers—if K′ stands for a complexingagent—are reacted in a way known in the art with at least one metaloxide or metal salt of an element of atomic numbers 20-29, 39, 42, 44,or 57-83 and then optionally in the cascade polymer complexes thusobtained, acid hydrogen atoms that are still present are completely orpartially substituted by cations of inorganic and/or organic bases,amino acids, or amino acid amides, and optionally still present freeterminal amino groups are optionally acylated—before or after the metalcomplexing.

[0146] Another aspect of this invention is represented by the newcompounds of general formula I′A

[0147] whereby

[0148] R^(1′), independently of one another, stand for a hydrogen atom,a metal ion equivalent of atomic numbers 20-29, 39, 42-44 or 57-83 or anacid protective group,

[0149] R² stands for a hydrogen atom, a methyl or an ethyl radical,which optionally is substituted with 1-2 hydroxy or 1 carboxy group(s)

[0150] R^(3′) stands for a

[0151] R⁴ stands for a straight-chain, branched, saturated orunsaturated C₁-C₃₀ alkyl chain, which optionally is interrupted by 1-10oxygen atoms, 1 phenylene group, 1 phenylenoxy group and/or optionallysubstituted by 1-5 hydroxy, 1-3 carboxy, 1-phenyl group(s),

[0152] U⁶ stands for a straight-chain, branched, saturated orunsaturated C₁-C₂₀ alkylene group optionally containing 1-5 imino, 1-3phenylene, 1-3 phenylenoxy, 1-3 phenylenimino, 1-5 amide, 1-2 hydrazide,1-5 carbonyl, 1-5 ethylenoxy, 1 urea, 1 thiourea, 1-2 carboxyalkylimino,1-2 ester groups; 1-10 oxygen, 1-5 sulfur and/or 1-5 nitrogen atom(s)and/or optionally substituted by 1-5 hydroxy, 1-2 mercapto, 1-5 oxo, 1-5thioxo, 1-3 carboxy, 1-5 carboxyalkyl, 1-5 ester and/or 1-3 aminogroup(s), whereby the phenylene groups that are optionally contained canbe substituted by 1-2 carboxy, 1-2 sulfo or 1-2 hydroxy groups,

[0153] T′ stands for a —C*O, —COOH, —N═C═O or —N═C═S group, and

[0154] C*O stands for an activated carboxyl group.

[0155] They are used as important intermediate products for theproduction of the cascade polymer complexes of general formula I.

[0156] As an example of an activated carbonyl group C*O in complexes orcomplexing agents K′, anhydride,-p-nitrophenyl ester,N-hydroxysuccinimide ester, pentafluorophenyl ester, and acid chloridecan be mentioned.

[0157] The addition or acylation that is carried out to introduce thecomplexing agent units is performed with substrates that contain desiredsubstituents K (optionally bound to a leaving group) or from which thedesired substituent is generated by the reaction.

[0158] As examples of addition reactions, the reaction of isocyanatesand isothiocyanates can be mentioned, whereby the reaction ofisocyanates is preferably performed in aprotic solvents, such as, e.g.,THF, dioxane, DMF, DMSO, methylene chloride at temperatures of between 0and 100° C., preferably between 0 and 50° C., optionally with theaddition of an organic base such as triethylamine, pyridine, lutidine,N-ethyldiisopropylamine, N-methylmorpholine. The reaction withisothiocyanates is generally performed in solvents, such as, e.g., wateror lower alcohols, such as, e.g., methanol, ethanol, isopropanol ortheir mixtures, DMF or mixtures of DMF and water at temperatures ofbetween 0 and 100° C., preferably between 0 and 50° C., optionally withthe addition of an organic or inorganic base, such as, e.g.,triethylamine, pyridine, lutidine, N-ethyldiisopropylamine,N-methylmorpholine, or alkaline-earth hydroxides, alkali hydroxides,such as, e.g., lithium, sodium, potassium, calcium hydroxide, or theircarbonates, such as, e.g., magnesium carbonate.

[0159] As examples of acylation reactions, the reaction of freecarboxylic acids according to the methods known to one skilled in theart [e.g., J. P. Greenstein, M. Winitz, Chemistry of the Amino Acids,John Wiley & Sons, N.Y. (1961), pp. 943-945] can be mentioned. It hasproven advantageous, however, to convert the carboxylic acid groupbefore the acylation reaction to an activated form, such as, e.g.,anhydride, active ester or acid chloride [e.g., E. Gross, J. Meienhofer,The Peptides, Academic Press, N.Y. (1979), Vol. 1, pp. 65-314; N. F.Albertson, Org. React. 12, 157 (1962)].

[0160] In the case of reaction with active ester, the literature knownto one skilled in the art [e.g., Houben-Weyl, Methoden der organischenChemie [Methods of Organic Chemistry], Georg Thieme Verlag, Stuttgart,Volume E 5 (1985), 633] can be cited. This reaction can be performedunder the conditions indicated above for the anhydride reaction.However, aprotic solvents, such as, e.g., methylene chloride,chloroform, can also be used.

[0161] In the case of acid chloride reactions, only aprotic solvents,such as, e.g., methylene chloride, chloroform, toluene or THF, attemperatures between −20 to 50° C., preferably between 0 to 30° C., areused. Further, literature known to one skilled in the art [e.g.,Houben-Weyl, Methoden der organischen Chemie, Georg-Thieme-Verlag,Stuttgart, (1974), Volume 15/2, pp. 355-364] can be cited.

[0162] If R^(1′) stands for an acid protective group, lower alkyl, aryland aralkyl groups, for example, the methyl, ethyl, propyl, butyl,phenyl, benzyl, diphenylmethyl, triphenylmethyl,bis-(p-nitrophenyl)-methyl groups, as well as trialkylsilyl groups, aresuitable.

[0163] The optionally desired cleavage of the protective groups takesplace according to the processes known to one skilled in the art, forexample by hydrolysis, hydrogenolysis, alkaline saponification of esterswith alkali in aqueous-alcoholic solution at temperatures of 0° C. to50° C. or in the case of tert-butyl esters with the aid oftrifluoroacetic acid.

[0164] Terminal amino groups that are optionally incompletely acylatedwith ligands or complexes can optionally be converted to amides orsemiamides. The reactions with acetic anhydride, succinic anhydride ordiglycolic anhydride can be mentioned as examples.

[0165] The introduction of the desired metal ions takes place in the wayin which it was disclosed, e.g., in German laid-open specification 34 01052, by the metal oxide or a metal salt (for example, the nitrate,acetate, carbonate, chloride or sulfate) of the element of atomicnumbers 20-29, 42, 44, 57-83 being dissolved or suspended in waterand/or a lower alcohol (such as methanol, ethanol or isopropanol) andbeing reacted with the solution or suspension of the equivalent amountof complexing ligand and then optionally existing acid hydrogen atoms ofthe acid groups being substituted by cations of inorganic and/or organicbases, amino acids or amino acid amides.

[0166] The introduction of the desired metal ions can take place both inthe stage of complexing agent I′A or I′B, i.e., before the coupling tothe cascade polymers, and after coupling of unmetalated ligands I′A, I′Bor I′C.

[0167] In this case, the neutralization takes place with the aid ofinorganic bases (for example, hydroxides, carbonates or bicarbonates)of, for example, sodium, potassium, lithium, magnesium or calcium and/ororganic bases, such as, i.a., primary, secondary and tertiary amines,such as, for example, ethanolamine, morpholine, glucamine, N-methyl andN,N-dimethylglucamine, as well as basic amino acids, such as, forexample, lysine, arginine and ornithine or of amides of originallyneutral or acid amino acids, such as, for example, hippuric acid,glycine acetamide.

[0168] For the production of neutral complex compounds, enough of thedesired bases can be added, for example, to the acid complex salts inaqueous solution or suspension that the neutral point is reached. Theobtained solution can then be evaporated to dryness in a vacuum. Often,it is advantageous to precipitate the formed neutral salts by addingwater-miscible solvents, such as, for example, lower alcohols (methanol,ethanol, isopropanol and others), lower ketones (acetone and others),polar ethers (tetrahydrofuran, dioxane, 1,2-dimethoxyethane and others)and thus to obtain easily isolated and readily purified crystallizates.It has proven especially advantageous to add the desired bases as earlyas during the complexing of the reaction mixture and thus to save aprocess step.

[0169] If the acid complex compounds contain several free acid groups,it is often suitable to produce neutral mixed salts, which contain bothinorganic and organic cations as counterions.

[0170] This can happen, for example, by the complexing ligands inaqueous suspension or solution being reacted with the oxide or salt ofthe element yielding the central ion and half of the amount of anorganic base required for neutralization, the formed complex salt beingisolated, optionally purified and then mixed with the required amount ofinorganic base for complete neutralization. The sequence of the additionof base can also be reversed.

[0171] The purification of the thus obtained cascade polymer complexestakes place, optionally after adjusting the pH to 6 to 8, preferablyabout 7, by adding an acid or base, preferably by ultrafiltration withmembranes of suitable pore size (e.g., Amicon®XM30, Amicon®YM10,Amicon®YM3) or gel filtration on, e.g., suitable Sephadex® gels.

[0172] In the case of neutral complex compounds, it is oftenadvantageous to provide the polymeric complexes with an anion exchanger,for example, IRA 67 (OH⁻ form) and optionally in addition with a cationexchanger, for example, IRC 50 (H⁺ form) for the separation of ioniccomponents.

[0173] The production of the cascade polymers carrying terminal aminogroups required for the coupling to complexing agents K′ (or else thecorresponding metal-containing complexes) generally proceeds fromnitrogen-containing cascade starters A(H)_(a) that can be produced bycommercially available methods or according to or analogously to methodsknown in the literature. The introduction of generations X, Y, Z and Wtakes place according to methods known in the literature [e.g., J.March, Advanced Organic Chemistry, 3rd ed.; John Wiley & Sons, (1985),364-381) by acylation or alkylation reactions with protected aminesexhibiting the desired structures, which contain functional groupscapable of bonding to the cascade nuclei, such as, e.g., carboxylicacids, isocyanates isothiocyanates or activated carboxylic acids (suchas, e.g., anhydrides, active esters, acid chlorides) or halides (suchas, e.g., chlorides, bromides, iodides), aziridine, mesylates, tosylatesor other leaving groups known to one skilled in the art.

[0174] It can be stressed, however, that the differentiation betweencascade nucleus A and reproduction units is purely formal. It can beadvantageous synthetically that formal cascade starter A(H)_(a) is notused, but rather the nitrogen atoms forming part of the cascade nucleusby definition are introduced first together with the first generation.Thus, e.g., for synthesis of the compound described in Example 1b), itis more advantageous not to alkylate the formal cascade nucleus trimesicacid triamide with e.g., benzyloxycarbonylaziridine (six-fold), butrather to react trimesic acid trichloride withbis[2-(benzyloxycarbonylamino)-ethyl]-amine (three-fold).

[0175] As amino protective groups, the benzyloxycarbonyl,tert-butoxycarbonyl, trifluoroacetyl, fluorenylmethoxycarbonyl, benzyland formyl groups familiar to one skilled in the art [Th. W. Greene, P.G. M. Wuts, Protective Groups in Organic Syntheses, 2nd ed, John Wileyand Sons (1991), pp. 309-385] can be mentioned. After cleavage of theseprotective groups, which also takes place according to methods known inthe literature, the next desired generation can be introduced into themolecule. In addition to this synthesis of a generation consisting oftwo reaction stages in each case (alkylation or acylation and protectivegroup cleavage), the simultaneous introduction of two, e.g., X—[Y]_(x),or several generations, e.g., X—[Y—(Z)_(y)]_(x), is also possible withonly two reaction stages. The synthesis of these multi-generation unitstakes place by alkylation or acylation of unprotected amines(“reproduction amine”)., exhibiting the structures of the desiredreproduction units, with a second reproduction amine, whose amine groupsare present in protected form.

[0176] The compounds of general formula A(H)_(a) required as cascadestarters are commercially available or can be produced according to oranalogously to methods known in the literature [e.g., Houben-Weyl,Methoden der org. Chemie, Georg-Thieme-Verlag, Stuttgart (1957), Vol.11/1; M. Micheloni et al., Inorg. Chem. (1985), 24, 3702; T. J. Atkinset al., Org. Synth., Vol. 58 (1978), 86-98; The Chemistry ofHeterocyclic Compounds: J. S. Bradshaw et al., Aza-Crown-Macrocycles,John Wiley & Sons, N.Y. (1993)]. As examples, there can be cited:

[0177] Tris(aminoethyl)amine [e.g., Fluka Chemie (Fluka Chemistry] AG,Switzerland; Aldrich-Chemie [Aldrich Chemistry], Germany];

[0178] tris(aminopropyl)amine [e.g., C. Woerner et al., Angew. Chem.(Applied Chem.) Int. Ed. Engl. (1993), 32, 1306];

[0179] diethylenetriamine [e.g., Fluka; Aldrich];

[0180] triethylenetetramine [e.g., Fluka; Aldrich];

[0181] tetraethylenepentamine [e.g., Fluka; Aldrich];

[0182] 1,3,5-tris(aminomethyl)benzene [e.g., T. M. Garrett et al., J.Am. Chem. Soc. (1991), 113, 2965];

[0183] trimesic acid triamide [e.g., H. Kurihara; Jpn. Kokai Tokyo KohoJP 04077481; CA 117, 162453];

[0184] 1,4,7-triazacyclononane [e.g., Fluka; Aldrich];

[0185] 1,4,7,10,13-pentaazacyclopentadecane [e.g., K. W. Aston, Eur.Pat. Appl. 0 524 161, CA 120, 44580];

[0186] 1,4,7,10-tetraazacyclododecane [e.g., Aldrich]

[0187] 1,4,8,11-tetraazacyclotetradecane [e.g., Fluka; Aldrich];

[0188] 1,4,7,10,13,16,19,22,25,28-decaazacyclotriacontane [e.g., A.Andres et al., J. Chem. Soc. Dalton Trans. (1993), 3507];

[0189] 1,1,1-tris(aminomethyl)ethane [e.g., R. J. Geue et al., Aust. J.Chem. (1983), 36, 927);

[0190] tris(aminopropyl)-nitromethane [e.g., G. R. Newkome et al.,Angew. Chem. 103, 1205 (1991) analogously to R. C. Larock, ComprehensiveOrganic Transformations, VCH Publishers, N.Y. (1989), 419-420]

[0191] 1,3,5,7-adamantanetetracarboxylic acid amide [e.g., H. Stetter etal., Tetr. Lett. 1967, 1841];

[0192] 1,2-bis[phenoxyethane]-3′,3″,5′,5″-tetracarboxylic acid amide[e.g., J. P. Collman et al.; J. Am. Chem. Soc. (1988), 110, 3477-86analogously to the instructions for Example 1b)];

[0193] 1,4,7,10,13,16,21,24-octaazabicyclo[8.8.8]hexacosane [e.g., P. H.Smith et al., J. Org. Chem. (1993), 58, 7939].

[0194] The production of the reproduction amines that contain theabove-mentioned functional groups required for the synthesis ofgenerations takes place according to or analogously to the instructionsdescribed in the experimental part or according to processes known inthe literature.

[0195] As examples, there can be mentioned:

[0196] N^(α),N^(ξ)-Di-benzyloxycarbonyl-lysine-p-nitrophenyl ester (seeinstructions for Example 1c)];

[0197] HOOC—CH₂OCH₂CO—N(CH₂CH₂NH—CO—O—CH₂C₆H₅)₂;

[0198] HOOC—CH₂N(CH₂CH₂NH—CO—O—CH₂C₆H₅)₂;

[0199] HOOC—CH₂CH₂CO—N(CH₂CH₂NH—COCF₃)₂ [to be produced according toinstructions for Example 3a), by starting frombis(trifluoroacetylaminoethyl)amine instead ofbis(benzyloxycarbonylaminoethyl)amine and from succinic anhydrid insteadof diglycolic anhydride];

[0200] HOOC—CH₂OCH₂CONH—C₆H₄—CH[CH₂CON(CH₂CH₂NH—CO—O—CH₂C₆H₅)₂]₂ [to beproduced analogously to instructions for Example 3a];

[0201] O═C═N—C₆H₄—CH[CH₂CON(CH₂CH₂NH—CO—O—CH₂C₆H₅)₂]₂

[0202] N-benzyloxycarbonyl-aziridine to be produced according to M.Zinic et al., J. Chem. Soc, Perkin Trans 1, 21-26 (1993)

[0203] N-benzyloxycarbonyl-glycine commercially available in, e.g.,Bachem, Calif.

[0204] to be produced according to C. J. Cavallito et al., J. Amer.Chem. Soc. 1943, 65, 2140, by starting fromN—CO—O—CH₂C₆H₅-(2-bromoethyl) amine instead of benzyl chloride [A. R.Jacobson et al., J. Med. Chem. (1991), 34, 2816].

[0205] The production of the complexes and complexing agents of generalformula I′A and I′B takes place according to or analogously to theinstructions described in the experimental part or according to methodsknown in the literature (see, e.g., European Patent Applications Nos. 0512 661, 0 430 863, 0 255 471 and 0 565 930).

[0206] Thus, the production of compounds of general formula I′A iscarried out, e.g., in that a group T″ is used as a precursor offunctional group T′, either in the meaning of a protected acid function,which can be converted to the free acid function independently of acidprotective groups R^(1′) according to the above-indicated process, or inthe meaning of a protected amine function, which unblocks according toprocesses known in the literature [Th. W. Greene, P. G. M. Wuts,Protective Groups in organic Synthesis, 2nd edition, John Wiley & Sons(1991), pp. 309-385] and then can be converted to the isocyanates orisothiocyanates [Methoden der Org. Chemie (Houben-Weyl), E 4, pp.742-749, 837-843, Georg Thieme Verlag, Stuttgart, N.Y. (1983)]. Suchcompounds can be produced according to or analogously to theinstructions that are described in the experimental part bymonoalkylation of cyclene with suitable α-halogenated acid amides [inaprotic solvents, such as, e.g., chloroform].

[0207] The production of compounds of general formula I′B can be carriedout, for example, in that a protected acid function is used as aprecursor of the activated carboxyl group-C*O, which can be converted tothe free acid function independently of acid protective groups R^(1′)according to the above-indicated processes and can be activatedaccording to the processes that are known in the literature and are alsodescribed above. Such compounds can be produced according to oranalogously to the instructions that are described in the experimentalpart or, for example, in that an amino acid derivative of generalformula II

[0208] in which

[0209] R^(5′) has the meaning indicated for R⁵, whereby hydroxy orcarboxy groups that are optionally contained in R⁵ are optionallypresent in protected form, and

[0210] V¹ is a straight-chain or branched C₁-C₆ alkyl group, a benzyl,trimethylsilyl, triisopropylsilyl, 2,2,2-trifluoroethoxy or2,2,2-trichloroethoxy group, whereby V¹ is different from R^(1″), isreacted with an alkylating agent of general formula III

[0211] in which

[0212] R^(1″) stands for a protective group, and

[0213] Ha1 stands for a halogen atom, such as Cl, Br or I, butpreferably Cl [see also M. A. Williams, H. Rapoport, J. Org. Chem. 58,1151 (1993)].

[0214] Preferred amino acid derivatives are the esters of naturallyoccurring α-amino acids.

[0215] The reaction of compound (II) with compound (III) is carried outpreferably in a buffered alkylation reaction, whereby an aqueousphosphate-buffer solution is used as buffer. The reaction is carried outat pH 7-9, but preferably at pH 8. The buffer concentration can bebetween 0.1-2.5 M, but preferably a 2 M phosphate-buffer solution isused. The temperature of the alkylation can be between 0 and 50° C.; thepreferred temperature is room temperature.

[0216] The reaction is carried out in a polar solvent, such as, e.g.,acetonitrile, tetrahydrofuran, 1,4-dioxane or 1,2-dimethoxyethane.Preferably, acetonitrile is used.

[0217] The production of the pharmaceutical agents according to theinvention takes place also in a way known in the art, by the complexcompounds according to the invention—optionally with the addition of theadditives that are commonly used in galenicals—being suspended ordissolved in aqueous medium and then the suspension or solutionoptionally being sterilized. Suitable additives are, for example,physiologically harmless buffers (such as, for example, tromethamine),additives of complexing agents or weak complexes (such as, for example,diethylenetriaminepentaacetic acid or the corresponding Ca-cascadepolymer complexes) or—if necessary—electrolytes, such as, for example,sodium chloride or—if necessary—antioxidants, such as, for example,ascorbic acid.

[0218] If suspensions or solutions of thefagents according to theinvention in water or physiological salt solution are desired forenteral administration or other purposes, they are mixed with one ormore adjuvant(s) that are commonly used in galenicals [for example,methylcellulose, lactose, mannitol] and/or surfactant(s) [for example,lecithins, Tween®, Myrj®] and/or flavoring substance(s) for tastecorrection [for example, ethereal oils].

[0219] In principle, it is also possible to produce the pharmaceuticalagents according to the invention even without isolating the complexsalts. In any case, special care must be used to undertake the chelationso that the salts and salt solutions according to the invention arepractically free of noncomplexed metal ions having a toxic effect.

[0220] This can be assured, for example, with the aid of colorindicators such as xylenol orange by control titrations during theproduction process. The invention therefore also relates to processesfor the production of complex compounds and their salts. As a lastprecaution, there is a purification of the isolated complex salt.

[0221] The pharmaceutical agents according to the invention containpreferably 1 μmol-1.3 mol/l of the complex salt and are generally dosedin amounts of 0.0001-5 mmol/kg. They are intended for enteral andparenteral administration. The complex compounds according to theinvention are used

[0222] 1. for NMR diagnosis and diagnostic radiology in the form oftheir complexes with the ions of elements with atomic numbers 21-29, 39,42, 44 and 57-83;

[0223] 2. for radiodiagnosis and radiotherapy in the form of theircomplexes with radioisotopes of the elements with atomic numbers 27, 29,31, 32, 37-39, 43, 49, 62, 64, 70, 75 and 77.

[0224] The agents according to the invention meet the variedrequirements for suitability as contrast media for nuclear spintomography. Thus, they are very well suited, after oral or parenteraladministration, for improving the image, obtained with the aid ofnuclear spin tomographs, in its informative value by increasing thesignal intensity. Further, they show the great effectiveness which isnecessary to load the body with the fewest possible amounts of foreignsubstances, and the good compatibility which is necessary to maintainthe noninvasive nature of the studies.

[0225] The good water solubility and low osmolality of the agentsaccording to the invention makes it possible to produce highlyconcentrated solutions, so that the volume load of the circulatorysystem can be held within reasonable limits, and to compare the dilutionthrough the bodily fluid, i.e., NMR diagnostic agents must be 100- to1000-fold more water-soluble than for NMR spectroscopy. Further, theagents according to the invention exhibit not only a high stability invitro, but also a surprisingly high stability in vivo, so that a releaseor an exchange of the ions—toxic in themselves—not covalently bound inthe complexes, in which the new contrast media are again completelyexcreted, takes place only extremely slowly.

[0226] In general, the agents according to the invention for use as NMRdiagnostic agents are dosed in amounts of 0.001-5 mmol/kg, preferably0.005-0.5 mmol/kg. Details of use are discussed, for example, in H. -J.Weinmann et al., Am. J. of Roentgenology 142, 619 (1984).

[0227] Especially low dosages (under 1 mg/kg of body weight) oforgan-specific NMR diagnostic agents can be used, for example, to detecttumors and myocardial infarction.

[0228] Further, the complex compounds according to the invention areused advantageously as susceptibility reagents and as shift reagents forin vivo NMR spectroscopy.

[0229] The agents according to the invention are also suitable asradiodiagnostic agents because of their advantageous radioactiveproperties and the good stability of the complex compounds contained inthem. Details of their use and dosage are described, e.g., in“Radiotracers for Medical Applications,” CRC Press, Boca Raton, Fla.

[0230] Another imaging method with radioisotopes is positron emissiontomography, which uses positron-emitting isotopes, such as, e.g., ⁴³Sc,⁴⁴Sc, ⁵²Fe, ⁵⁵Co and ⁶⁸Ga (Heiss, W. D.; Phelps, M. E.; PositronEmission Tomography of the Brain, Springer Verlag Berlin, Heidelberg,N.Y. 1983).

[0231] The compounds according to the invention are also suitable,surprisingly enough, for differentiating malignant and benign tumors inareas without blood-brain barriers.

[0232] They are also distinguished in that they are eliminatedcompletely from the body and thus are well compatible.

[0233] Since the substances according to the invention are concentratedin malignant tumors (no diffusion in healthy tissue, but highpermeability of tumor vessels), they can also assist in the radiationtherapy of malignant tumors. The latter is distinguished from thecorresponding diagnosis only by the amount and type of the isotope used.The object, in this case, is the destruction of tumor cells byhigh-energy shortwave radiation with a smallest possible range ofaction. For this purpose, interactions of the metals contained in thecomplexes (such as, e.g., iron or gadolinium) are used with ionizingradiations (e.g., x rays) or with neutron rays. By this effect, thelocal radiation dose is significantly increased on the spot where themetal complex is found (e.g., in tumors). To produce the same radiationdose in the malignant tissue, the radiation exposure for healthy tissuecan be considerably reduced with the use of such metal complexes andthus side effects that are stressful to the patients are avoided. Themetal complex conjugates according to the invention are thereforesuitable also as radiosensitizing substances in radiation therapy ofmalignant tumors (e.g., use of Mössbauer effects or in neutron capturetherapy). Suitable β-emitting ions are, for example, ⁴⁶Sc, ⁴⁷Sc, ⁴⁸Sc,⁷²Ga, ⁷³Ga and ⁹⁰Y. Suitable α-emitting ions exhibiting small half-livesare, for example, ²¹¹Bi, ²¹²Bi, ²¹³Bi and ²¹⁴Bi, and ²¹²Bi is preferred.A suitable photon- and electron-emitting ion is ¹⁵⁸Gd, which can beobtained from ¹⁵⁷Gd by neutron capture.

[0234] If the agent according to the invention is intended for use inthe variant of radiation therapy proposed by R. L. Mills et al. (NatureVol. 336, (1988), p. 787), the central ion must be derived from aMbssbauer isotope, such as, for example, ⁵⁷Fe or ¹⁵¹Eu.

[0235] In the in vivo administration of the therapeutic agents accordingto the invention, the latter can be administered together with asuitable vehicle, such as, for example, serum, or physiological commonsalt solution and together with another protein, such as, for example,human serum albumin. In this case, the dosage depends on the type ofcellular disorder, the metal ion used and the type of imaging method.

[0236] The therapeutic agents according to the invention areadministered parenterally, preferably i.v.

[0237] Details of use of radiotherapeutic agents are discussed, e.g., inR. W. Kozak et al. TIBTEC, October 1986, 262.

[0238] The agents according to the invention are very well suited asx-ray contrast media, especially for computer tomography (CT), and it isespecially to be emphasized that no signs of the anaphylaxis-likereactions, known from the iodine-containing contrast media, can bedetected with them in biochemical-pharmacological studies. They areespecially valuable because of the advantageous absorption properties inthe areas of higher tube voltages for digital subtraction techniques.

[0239] In general, the agents according to the invention are dosed foruse as x-ray contrast media analogously to, for example,meglumine-diatrizoate in amounts of 0.1-5 mmol/kg, preferably 0.25-1mmol/kg.

[0240] Details of use of x-ray contrast media are discussed, forexample, in Barke, Rontgenkontrastmittel [X-Ray Contrast Media], G.Thieme, Leipzig (1970) and P. Thurn, E. Bucheler “Einfuhrung in dieRöntgendiagnostik [Introduction to Diagnostic Radiology],” G. Thieme,Stuttgart, N.Y. (1977).

[0241] In general, it has been possible to synthesize new complexingagents, metal complexes and metal complex salts, which open up newpossibilities in diagnostic and therapeutic medicine.

[0242] Without further elaboration, it is believed that one skilled inthe art can, using the preceding description, utilize the presentinvention to its fullest extent. The following preferred specificembodiments are, therefore, to be construed as merely illustrative, andnot limitative of the remainder of the disclosure in any way whatsoever.

[0243] In the foregoing and in the following examples, all temperaturesare set forth uncorrected in degrees Celsius and unless otherwiseindicated, all parts and percentages are by weight.

[0244] The entire disclosure of all applications, patents andpublications, cited above and below, and of corresponding GermanApplication No. 195 25 924.6, filed on Jul. 4, 1995, are herebyincorporated by reference.

EXAMPLE 1

[0245] a) Bis[2-(benzyloxycarbonylamino)-ethyl]-amine

[0246] 51.5 g (500 mmol) of diethylenetriamine and 139 ml (1 mol) oftriethylamine are dissolved in dichloromethane and mixed at −20° C. with161 g of benzyl cyanoformate (Fluka) in dichloromethane and then stirredovernight at room temperature. After the reaction is completed,concentration by evaporation is performed during draw-off, the residueis taken up in diethyl ether, the organic phase is washed with sodiumcarbonate solution and dried with sodium sulfate. The filtrate is mixedwith hexane, the precipitate is filtered out and dried.

[0247] Yield: 163.4 g (88% of theory)

[0248] Elementary analysis:

[0249] Cld: C, 64.67; H, 6.78; N, 11.31

[0250] Fnd: C, 64.58; H, 6.83; N, 11.28

[0251] b)N,N,N′,N′,N″,N″-Hexakis[2-(benzyloxycarbonylamino)-ethyl]-trimesic AcidTriamide

[0252] 13.27 g (50 mmol) of trimesic acid trichloride (Aldrich) and 34.7ml (250 mmol) of triethylamine are dissolved in dimethylformamide (DMF)and mixed at 0° C. with 65.0 g (175 mmol) of the amine described inExample 1a) and then stirred overnight at room temperature. The solutionis concentrated by evaporation in a vacuum, and the residue ischromatographed on silica gel with ethyl acetate.

[0253] Yield: 39.4 g (62% of theory)

[0254] Elementary analysis:

[0255] Cld: C, 65.24; H, 5.95; N, 9.92

[0256] Fnd: C, 65.54; H, 5.95; N, 9.87

[0257] C) N^(α),N^(ξ)-Bis(N,N′-dibenzyloxycarbonyl-lysyl)-lysine,Protected “tri-lysine”

[0258] 3.6 g (20 mmol) of lysine-hydrochloride and 6.95 ml (50 mmol) oftriethylamine are dissolved in DMF, mixed with 26.8 g (50 mmol) ofN^(α),N^(ξ)-dibenzyloxycarbonyl-lysine-p-nitrophenylester (Bachem) andstirred for 2 days at room temperature. After the reaction is completed,it is concentrated by evaporation in a vacuum, the residue is taken upin ethyl acetate and shaken out with diluted hydrochloric acid. Theorganic phase is dried with sodium sulfate, the solvent is concentratedby evaporation, and the residue is chromatographed with ethylacetate/ethanol in a step gradient.

[0259] Yield: 10.7 g (57% of theory)

[0260] Elementary analysis:

[0261] Cld: C, 63.95; H, 6.65; N, 8.95

[0262] Fnd: C, 63.63; H, 6.69; N, 8.93

[0263] d) Completely Protected Benzyloxycarbonyl-24-Polyamine Based onN,N,N′,N′,N″,N″-hexakis[2-(trilysyl-amino)-ethyl)-trimesic Acid Triamide

[0264] 1.27 g (1 mmol) of the hexa-benzyloxycarbonylamine described inExample 1b) is dissolved in glacial acetic acid and mixed with 33%hydrogen bromide in glacial acetic acid while being stirred. After 60minutes, the incipient precipitation is completed with diethyl ether,the hexaamine-hydrobromide produced is washed with ether, dried in avacuum and used in the subsequent reaction described below withoutfurther purification.

[0265] Yield: 0.95 g (quantitative)

[0266] 7.0 g (7.5 mmol) of the protected “tri-lysine” described inExample 1c), 1.2 g (7.5 mmol) of 1-hydroxybenzotriazole and 2.4 g (7.5mmol) of 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluroniumtetrafluoroborate (TBTU; Peboc Limited, UK) are dissolved in DMF andstirred for 15 minutes. This solution is then mixed with 5.16 ml (30mmol) of N-ethyldiisopropylamine and with 0.95 g (1 mmol) of thehexaamine-hydrobromide described above, and it is stirred overnight atroom temperature. After the reaction is completed, it is concentrated byevaporation in a vacuum, and the residue is chromatographed on silicagel with ethyl acetate/ethanol (2:1).

[0267] Yield: 4.55 g (76% of theory)

[0268] Elementary analysis:

[0269] Cld: C, 64.35; H, 6.71; N, 10.52

[0270] Fnd: C, 64.08; H, 6.57; N, 10.29

[0271] e) 2-Bromopropionylglycine-benzyl Ester

[0272] 55.9 g (326.1 mmol) of 2-bromopropionic acid chloride is added indrops at 0° C. to 100 g (296.4 mmol) of glycine benzylester-p-toluenesulfonic acid salt and 33.0 g (326.1 mmol) oftriethylamine in 400 ml of methylene chloride. The temperature is notallowed to exceed 5° C. After addition is completed, it is stirred forone hour at 0° C., then for 2 hours at room temperature. 500 ml of icewater is added, and the water phase is set at pH 2 with 10% aqueoushydrochloric acid. The organic phase is separated, washed once each with300 ml of 5% aqueous soda solution and 400 ml of water. The organicphase is dried on magnesium sulfate and evaporated to dryness in avacuum. The residue recrystallizes from diisopropyl ether.

[0273] Yield: 68.51 g (75% of theory) of a colorless crystalline powder

[0274] Melting point: 69-70° C.

[0275] Elementary analysis:

[0276] Cld: C, 46.76; H, 7.19; N, 4.54 Br 25.92

[0277] Fnd: C, 46.91; H, 7.28; N, 4.45 Br 25.81

[0278] f)1-[4-(Benzyloxycarbonyl)-1-methyl-2-oxo-3-azabutyl]-1,4,7,10-tetraazacyclododecane

[0279] 50 g (162.2 mmol) of the title compound of Example 1e) is addedto 55.8 g (324.4 mmol) of 1,4,7,10-tetraazacyclododecane, dissolved in600 ml of chloroform, and it is stirred overnight at room temperature.500 ml of water is added, the organic phase is separated and in eachcase washed twice with 400 ml of water. The organic phase is dried onmagnesium sulfate and evaporated to dryness in a vacuum. The residue ischromatographed on silica gel (mobile solvent:chloroform/methanol/aqueous 25% ammonia=10:5:1).

[0280] Yield: 40.0 g [63% of theory relative to the le) used] of aslightly yellowish viscous oil.

[0281] Elementary analysis:

[0282] Cld: C, 61.36; H, 8.50; N, 17.89

[0283] Fnd: C, 61.54; H, 8.68; N, 17.68

[0284] g)10-[4-(Benzyloxycarbonyl)-1-methyl-2-oxo-3-azabutyl]-1,4,7-tris(tert-butoxycarbonylmethyl)-1,4,7,10-tetraazacyclododecane(Sodium Bromide Complex)

[0285] 33 g (169 mmol) of bromoacetic acid-tert-butyl ester is added to20 g (51.08 mmol) of the title compound of Example 1f) and 17.91 g (169mmol) of sodium carbonate in 300 ml of acetonitrile, and it is stirredfor 24 hours at 60° C. It is cooled to 0° C., the salts are filteredout, and the filtrate is evaporated to dryness. The residue ischromatographed on silica gel (mobile solvent: ethyl acetate/ethanol:15:1). The fractions that contain the product are concentrated byevaporation, and the residue recrystallizes from diisopropyl ether.

[0286] Yield: 34.62 g (81% of theory) of a colorless crystalline powder

[0287] Melting point: 116-117° C.

[0288] Elementary analysis:

[0289] Cld: C, 54.54; H, 7.59; N, 8.37 Na 2.74 Br 9.56

[0290] Fnd: C, 54.70; H, 7.65; N, 8.24 Na 2.60 Br 9.37

[0291] h) 10- (4-Carboxy-1-methyl-2-oxo-3-azabutyl)-1,4,7-tris(tert-butoxycarbonylmethyl)-1,4,7,10-tetraazacyclododecane (SodiumBromide Complex)

[0292] 30 g (35.85 mmol) of the title compound of Example 1g) isdissolved in 500 ml of isopropanol, and 3 g of palladium catalyst (10%Pd/C) is added. It is hydrogenated overnight at room temperature.Catalyst is filtered out, the filtrate is evaporated to dryness in avacuum and recrystallized from acetone.

[0293] Yield: 22.75 g (85% of theory) of a colorless crystalline powder

[0294] Melting point: 225° C. (decomposition)

[0295] Elementary analysis:

[0296] Cld: C, 49.86; H, 7.69; N, 9.38 Na 3.07 Br 10.71

[0297] Fnd: C, 49.75; H, 7.81; N, 9.25 Na 2.94 Br 10.58

[0298] i) 24-mer N-(5-DO3A-yl-4-oxo-3-azahexanoyl)-cascade polyamidebased on N,N,N′,N′,N″,N″-hexakis(2-(trilysylamino)-ethyl]-trimesic AcidTriamide*)

[0299] 6.0 g (1 mmol) of the poly-benzyloxycarbonylamine described inExample 1d) is dissolved in glacial acetic acid and mixed with 33%hydrogen bromide in glacial acetic acid while being stirred. After 3hours, the incipient precipitation is completed with diethyl ether, the24-amine-hydrobromide produced is washed with ether and dried in avacuum.

[0300] 35.84 g (48 mmol) of the acid described in Example 1 h) above isdissolved in DMF, mixed with 7.35 g (48 mmol) of 1-hydroxybenzotriazole,with 15.41 g (48 mmol) of TBTU (Peboc Limited, UK) and with 49.3 ml (288mmol) of N-ethyldiisopropylamine, and it is stirred for 20 minutes atroom temperature. This solution is then mixed with the (1 mmol)24-amine-hydrobromide described above, and it is stirred for 4 days atroom temperature. The solution is concentrated by evaporation in avacuum, the remaining oil is cooled in an ice bath and mixed withtrifluoroacetic acid, stirred overnight at room temperature and thenprecipitated with diethyl ether. The precipitate is dried in a vacuum,taken up in water, set at pH 7, a YM3 Amicon®-ultrafiltration membraneis used to remove low-molecular portions, and the retentate isultimately membrane-filtered and freeze-dried.

[0301] Yield: 13.5 g (83% of theory)

[0302] H₂O content (Karl-Fischer): 6.2%

[0303] Elementary analysis (relative to anhydrous substance):

[0304] Cld: C, 45.82; H, 6.09; N, 15.07 Na 10.79

[0305] Fnd: C, 45.56; H, 6.15; N, 14.80 Na 10.52

[0306] k) 24-mer-Gd-complex of N-(5-DO3A-yl-4-oxo-3-azahexanoyl)-cascadepolyamide based onN,N,N′,N′,N″,N″-hexakis[2-(trilysylamino)-ethyl]-trimesic Acid Triamide

[0307] 8.13 g (0.5 mmol) of the complexing agent acid described inExample 1i) above is set at pH 3 in water with diluted hydrochloricacid, mixed with 2.17 g (6 mmol) of Gd₂O₃, stirred for 30 minutes at 80°C., set at pH 7 after cooling and desalinated-with a YM3 AMICON®ultrafiltration membrane. The retentate is ultimately membrane-filteredand freeze-dried.

[0308] Yield: 8.89 g (92.1% of theory)

[0309] H₂O content (Karl-Fischer): 9.6%

[0310] Gd determination (AAS): 19.6%

[0311] Elementary analysis (relative to anhydrous substance):

[0312] Cld: C, 40.26; H, 5.35; N, 13.24 Gd 21.62

[0313] Fnd: C, 39.98; H, 5.51; N, 13.42 Gd 21.37

EXAMPLE 2

[0314] a) 2-Bromopropionyl-B-alanine-benzyl Ester

[0315] 53.65 g (313 mmol) of 2-bromopropionic acid chloride is added indrops at 0° C. to 100 g (285 mmol) of B-alanine-benzylester-p-toluenesulfonic acid salt and 31.67 g (313 mmol) oftriethylamine in 400 ml of methylene chloride. The temperature is notallowed to exceed 5° C. After addition is completed, it is stirred for 1hour at 0° C., then for 2 hours at room temperature. 500 ml of ice wateris added, and the water phase is set at pH 2 with 10% aqueoushydrochloric acid. The organic phase is separated, washed once each with300 ml of 5% aqueous hydrochloric acid, 300 ml of 5% aqueous sodasolution and 400 ml of water. The organic phase is dried on magnesiumsulfate and evaporated to dryness in a vacuum. The residuerecrystallizes from diisopropyl ether.

[0316] Yield: 71.36 g (78% of theory) of a colorless crystalline powder

[0317] Elementary analysis:

[0318] Cld: C, 48.46; H, 7.51; N, 4.35 Br 24.80

[0319] Fnd: C, 48.29; H, 7.65; N, 4.25 Br 24.61

[0320] b)1-[5-(Benzyloxycarbonyl)-1-methyl-2-oxo-3-azapentyl]-1,4,7,10-tetraazacyclododecane

[0321] 50 g (155.2 mmol) of the title compound of Example 2a) is addedto 53.32 g (310 mmol) of 1,4,7,10-tetraazacyclododecane dissolved in 600ml of chloroform, and it is stirred overnight at room temperature. 500ml of water is added, the organic phase is separated, and it is washedtwice in each case with 400 ml of water. The organic phase is dried onmagnesium sulfate and evaporated to dryness in a vacuum. The residue ischromatographed on silica gel (mobile solvent:chloroform/methanol/aqueous 25% ammonia: 10/5/1).

[0322] Yield: 38.39 g [61% of theory relative to the 2a) used] of alight yellowish viscous oil.

[0323] Elementary analysis:

[0324] Cld: C, 62.20; H, 8.70; N, 17.27

[0325] Fnd: C, 62.05; H, 8.81; N, 17.15

[0326] c)10-[5-(Benzyloxycarbonyl)-1-methyl-2-oxo-3-azapentyl]-1,4,7-tris(tert-butoxycarbonyl-methyl)-1,4,7,10-tetraazacyclododecane(Sodium Bromide Complex)

[0327] 31.8 g (163 mmol) of bromoacetic acid-tert-butyl ester is addedto 20 g (49.32 mmol) of the title compound of Example 2b) and 17.28 g(163 mmol) of sodium carbonate in 300 ml of acetonitrile, and it isstirred for 24 hours at 60° C. It is cooled to 0° C., salts are filteredout, and the filtrate is evaporated to dryness. The residue ischromatographed on silica gel (mobile solvent: ethylacetate/ethanol=10/1). The fractions that contain the product areconcentrated by evaporation, and the residue recrystallizes fromdiisopropyl ether.

[0328] Yield: 31.89 g (76% of theory) of a colorless, crystalline powder

[0329] Elementary analysis:

[0330] Cld: C, 55.05; H, 7.70; N, 8.23 Na 2.69 Br 9.40

[0331] Fnd: C, 55.17; H, 7.85; N, 8.10 Na 2.51 Br 9.30

[0332] d)10-(5-(Carboxy)-1-methyl-2-oxo-3-azapentyl)-1,4,7-tris(tert-butoxycarbonylmethyl)-1,4,7,10-tetraazacyclododecane(Sodium Bromide Complex)

[0333] 30 g (35.26 mmol) of the title compound of Example 2c) isdissolved in 500 ml of isopropanol, and 3 g of palladium catalyst (10%Pd/C) is added. It is hydrogenated overnight at room temperature.Catalyst is filtered out, the filtrate is evaporated to dryness in avacuum and recrystallized from acetone.

[0334] Yield: 24.41 g (91% of theory) of a colorless, crystalline powder

[0335] Elementary analysis:

[0336] Cld: C, 50.52; H, 7.82; N, 9.21 Na 3.01 Br 10.52

[0337] Fnd: C, 50.41; H, 7.95; N, 9.10 Na 2.91 Br 10.37

[0338] e) 24-mer N-(6-DO3A-yl-5-oxo-4-azaheptanoyl)-cascade polyamidebased on N,N,N′,N′,N″,N″-hexakis[2-(trilysylamino)-ethyl]-trimesic AcidTriamide

[0339] 6.0 g (1 mmol) of the poly-benzyloxycarbonylamine described inExample 1d) is dissolved in glacial acetic acid and mixed with 33%hydrogen bromide in glacial acetic acid while being stirred. After 3hours, the incipient precipitation is completed with diethyl ether, the24-amine-hydrobromide produced is washed with ether and dried in avacuum.

[0340] 36.52 g (48 mmol) of the acid described in Example 2d) above isdissolved in DMF, mixed with 7.35 g (48 mmol) of 1-hydroxybenzotriazole,with 15.41 g (48 mmol) of TBTU (Peboc Limited, UK) and with 49.3 ml (288mmol) of N-ethyldiisopropylamine, and it is stirred for 20 minutes atroom temperature. This solution is then mixed with the (1 mmol)24-amine-hydrobromide described above and stirred for 4 days at roomtemperature. The solution is concentrated by evaporation in a vacuum,the remaining oil is cooled in an ice bath and mixed withtrifluoroacetic acid, stirred overnight at room temperature and thenprecipitated with diethyl ether. The precipitate is dried in a vacuum,taken up in water, set at pH 7, a YM3 Amicon® ultrafiltration membraneis used to remove low-molecular portions, and the retentate isultimately membrane-filtered and freeze-dried.

[0341] Yield: 14.4 g (85% of theory)

[0342] H₂O content (Karl-Fischer): 8.7%

[0343] Elementary analysis (relative to anhydrous substance):

[0344] Cld: C, 46.82; H, 5.98; N, 14.79 Na 10.59

[0345] Fnd: C, 47.04; H, 6.23; N, 14.96 Na 10.26

[0346] f) 24-mer-Gd Complex ofN-(6-DO3A-yl-5-oxo-4-azaheptanoyl)-cascade polyamide based onN,N,N′,N′,N″,N″-hexakis[2-(trilysylamino)-ethyl]-trimesic Acid Triamide

[0347] 8.5 g (0.5 mmol) of the complexing agent acid described inExample 2e) above is set at pH 3 in water with diluted hydrochloricacid, mixed with 2.17 g (6 mmol) of Gd₂O₃, stirred for 30 minutes at 80°C., set at pH 7 after cooling and desalinated with a YM3 AMICON®ultrafiltration membrane. The retentate is ultimately membrane-filteredand freeze-dried.

[0348] Yield: 8.50 g (88% of theory)

[0349] H₂O content (Karl-Fischer): 7.9%

[0350] Gd determination (AAS): 19.4%

[0351] Elementary analysis (relative to anhydrous substance):

[0352] Cld: C, 41.12; H, 5.52; N, 12.99 Gd 21.21

[0353] Fnd: C, 40.86; H, 5.34; N, 13.25 Gd 20.95

EXAMPLE 3

[0354] a)N,N′-Bis(benzyloxycarbonyl)-3-[carboxymethoxyacetyl]-3-azapentane-1,5-diamine

[0355] 37.14 g (100 mmol) of the bis(benzyloxycarbonyl-aminoethyl)-aminedescribed in Example 1a) is dissolved in DMF, mixed in an ice bath with17.4 g (150 mmol) of diglycolic anhydride (Janssen Chimica) and 21 ml(150 mmol) of triethylamine and then stirred overnight at roomtemperature. The solution is concentrated by evaporation in a vacuum,the residue is taken up in ethyl acetate and shaken out with dilutedhydrochloric acid. The organic phase is dried with sodium sulfate andafter the drying agent is filtered, it is crystallized by adding hexane.

[0356] Yield: 41.4 g (85% of theory)

[0357] Elementary analysis:

[0358] Cld: C, 59.13; H, 6.00; N, 8.62

[0359] Fnd: C, 58.99; H, 5.93; N, 8.70

[0360] b)N,N′,N″,N′″-Tetrakis{8-(benzyloxycarbonylamino)-6-[2-(benzyloxycarbonylaminoethyl]-5-oxo-3-oxaoctanoyl}cyclene

[0361] 345 mg (2 mmol) of 1,4,7,10-tetraazacyclododecane (cyclene;Fluka) is azeotropically dehydrated with toluene. A solution of 4.88 g(10 mmol) ofN,N′-bis(benzyloxycarbonyl)-3-[carboxymethoxyacetyl]-3-azapentane-1,5-diamine(Example 3a)] in tetrahydrofuran (THF) as well as 2.47 g (10 mmol) of2-ethoxy-1-ethoxycarbonyl-1,2-dihydroquinoline (EEDQ; Fluka) are addedto the cooled solution of cyclene in toluene at room temperature, and itis stirred overnight. After the reaction is completed, the product isprecipitated by adding hexane, decanted from solvent and reprecipitatedonce more from THF/hexane and then from THF/toluene. After drying in avacuum, 2.78 g (68% of theory) of a pale yellow solid is obtained.

[0362] Elementary analysis:

[0363] Cld: C, 60.93; H, 6.29; N, 10.93

[0364] Fnd: C, 60.68; H, 6.40; N, 10.97

[0365] c) Completely Protected benzyloxycarbonyl-32-polyamine Based on32-amine Condensed with N^(α),N^(ξ)-bis(lysyl)-lysine (“tri-lysine) fromN,N′,N″,N′″-tetrakis{8-benzyloxycarbonylamino)-6-[2-(benzyloxycarbonylamino)-ethyl]-5-oxo-3-oxaoctanoyl}cyclene

[0366] 2.05 g (1 mmol) of the octa-benzyloxycarbonylamine described inExample 3b) is dissolved in glacial acetic acid and mixed with 33%hydrogen bromide in glacial acetic acid while being stirred. After 90minutes, the incipient precipitation is completed with diethyl ether,the octa-amine-hydrobromide produced is washed with ether, dried in avacuum and used in the subsequent reaction described below withoutfurther purification.

[0367] Yield: 1.6 g (quantitative)

[0368] 9.4 g (10 mmol) of the protected “tri-lysine” described inExample 1c), 1.5 g (10 mmol) of 1-hydroxybenzotriazole and 3.2 g (10mmol) of 2-(1H-benzotriazol-1-yl)-1,1,3,3,-tetramethyluroniumtetrafluoroborate (TBTU; Peboc Limited, UK) are dissolved in DMF andstirred for 15 minutes. This solution is then mixed with 5.16 ml (30mmol) of N-ethyldiisopropylamine and with 1.6 g (1 mmol) of theoctaamine-hydrobromide described above, and it is stirred overnight atroom temperature. After the reaction is completed, it is concentrated byevaporation in a vacuum, and the residue is chromatographed on silicagel with dichloromethane/methanol (10:1).

[0369] Yield: 6.0 g (72% of theory)

[0370] Elementary analysis:

[0371] Cld: C, 63.32; H, 6.76; N, 10.74

[0372] Fnd: C, 62.98; H, 6.91; N, 10.43

[0373] d) 32-mer N-(5-DO3A-yl-4-oxo-3-azahexanoyl)-cascade PolyamideBased on the 32-mer Amine Described in Example 3c) above

[0374] 8.35 g (1 mmol) of the 32-mer-benzyloxycarbonylamine described inExample 3c) is dissolved in glacial acetic acid and mixed with 33%hydrogen bromide in glacial acetic acid while being stirred. After 3hours, the incipient precipitation is completed with diethyl ether, the32-amine-hydrobromide produced is washed with ether and dried in avacuum.

[0375] 47.8 g (64 mmol) of the acid described in Example 1 h) isdissolved in DMF, mixed with 9.8 g (64 mmol) of 1-hydroxybenzotriazole,with 20.5 g (64 mmol) of TBTU (Peboc Limited, UK) and with 65.7 ml (384mmol) of N-ethyldiisopropylamine, and it is stirred for 20 minutes atroom temperature. This solution is then mixed with the (1 mmol)32-amine-hydrobromide described above and stirred for 4 days at roomtemperature. The solution is concentrated by evaporation in a vacuum,the remaining oil is cooled in an ice bath and mixed withtrifluoroacetic acid, stirred overnight at room temperature and thenprecipitated with diethyl ether. The precipitate is dried in a vacuum,taken up in water, set at pH 7, a YM3 Amicon® ultrafiltration membraneis used to remove low-molecular portions, and the retentate isultimately membrane-filtered and freeze-dried.

[0376] Yield: 17.2 g (76.4% of theory)

[0377] H₂O content (Karl-Fischer): 7.6%

[0378] Elementary analysis (relative to anhydrous substance):

[0379] Cld: C, 45.73; H, 6.12; N, 15.08 Na 10.61

[0380] Fnd: C, 45.89; H, 6.30; N, 14.84 Na 10.31

[0381] e) 32-mer-Gd Complex of N-(5-DO3A-yl-4-oxo-3-azahexanoyl)-cascadePolyamide Based on the 32-mer Amine Described in Example 3c)

[0382] 10.4 g (0.5 mmol) of the complexing agent acid described inExample 3d) above is set at pH 3 in water with diluted hydrochloricacid, mixed with 2.89 g (8 mmol) of Gd₂O₃, stirred for 30 minutes at 80°C., set at pH 7 after cooling and desalinated with a YM3 AMICON®ultrafiltration membrane. The retentate is ultimately membrane-filteredand freeze-dried.

[0383] Yield: 12.1 g (91.1% of theory)

[0384] H₂O content (Karl-Fischer): 11.0%

[0385] Gd determination (AAS): 18.6%

[0386] Elementary analysis (relative to anhydrous substance):

[0387] Cld: C, 40.26; H, 5.39; N, 13.28 Gd 21.30

[0388] Fnd: C, 40.10; H, 5.21; N, 13.04 Gd 21.03

[0389] The ytterbium complex is obtained analogously with Yb₂(CO₃)₃:

[0390] Elementary analysis (relative to anhydrous substance):

[0391] Cld: C, 39.42; H, 5.28; N, 13.00 Yb 22.94

[0392] Fnd: C, 39.29; H, 5.40; N, 12.81 Yb 22.65

EXAMPLE 4

[0393] a) Hexaethylene Glycol Monomethyl ether-p-toluenesulfonic AcidEster

[0394] 14.3 g (75 mmol) of p-toluenesulfonic acid chloride is added inportions at 0° C. to 20 g (67.49 mmol) of hexaethylene glycol monomethylether and 7.59 g (75 mmol) of triethylamine in 200 ml of chloroform, andit is then stirred for 4 hours at this temperature. It is evaporated todryness in a vacuum, and the residue is chromatographed on silica gel(mobile solvent: chloroform/methanol=5/1).

[0395] Yield: 27.67 g (91% of theory) off a sheetlike, vitreous solid

[0396] Elementary analysis:

[0397] Cld: C, 53.32; H, 7.61 S 7.12

[0398] Fnd: C, 53.15; H, 7.70 S 7.03

[0399] b) 1-Benzyloxy-5- (benzyloxycarbonyl)-2-chloro-3-oxo-4-azapentane

[0400] 76 g (326.1 mmol) of 2-chloro-3-(benzyloxy)-propionic acidchloride (produced according to Inorg. Chem. Vol. 31; 2422, 1992) isadded in drops to 100 g (296.4 mmol) of glycine benzylester-p-toluenesulfonic acid salt and 33.0 g (326.1 mmol) oftriethylamine in 400 ml of methylene chloride at 0° C., and it isstirred for 2 hours at this temperature. 500 ml of ice water is added,and the water phase is set at pH 2 with 10% aqueous hydrochloric acid.The organic phase is separated, washed once each with 300 ml of 5%aqueous hydrochloric acid, 300 ml of 5% aqueous soda solution and 400 mlof water. The organic phase is dried on magnesium sulfate and evaporatedto dryness in a vacuum. The residue is chromatographed on silica gel(mobile solvent: methylene chloride/hexane/acetone =15/5/1).

[0401] Yield: 75.07 g (70% of theory) of a pale yellow-colored viscousoil

[0402] Elementary analysis:

[0403] Cld: C, 63.07; H, 5.57; N, 3.87 Cl 9.80

[0404] Fnd: C, 63.17; H, 5.65; N, 3.75 Cl 9.63

[0405] c)1-[4-(Benzyloxycarbonyl)-1-(benzyloxymethyl)-2-oxo-3-azabutyl]-1,4,7,10-tetraazacyclododecane

[0406] 70 g (193.5 mmol) of the title compound of Example 4b) and 11.1 g(64.5 mmol) of 1,4,7,10-tetraazacyclododecane are dissolved in 70 ml ofdimethylformamide and stirred for 2 days at 50° C. It is evaporated todryness in a vacuum, the residue is taken up in 700 ml of water andextracted twice with 250 ml of chloroform each. The organic phase isdried on magnesium sulfate and evaporated to dryness in a vacuum. Theresidue is chromatographed on silica gel (mobile solvent:chloroform/methanol/25% aqueous ammonia=10/5/1).

[0407] Yield: 13.16 g (41% of theory relative to cyclene) of a viscous,colorless oil

[0408] Elementary analysis:

[0409] Cld: C, 65.17; H, 7.90; N, 14.07

[0410] Fnd: C, 65.24; H, 7.77; N, 14.18

[0411] d)10-[4-(Benzyloxycarbonyl)-1-(benzyloxymethyl)-2-oxo-3-azabutyl]-1,4,7-tris(tert-butoxycarbonylmethyl)-1,4,7,10-tetraazacyclododecane(sodium bromide complex)

[0412] 16.81 g (86.2 mmol) of bromoacetic acid-tert-butyl ester is addedto 13 g (26.12 mmol) of the title compound of Example 4c) and 9.14 g(86.2 mmol) of sodium carbonate in 200 ml of acetonitrile, and it isstirred for-24 hours at 60° C. It is cooled to 0° C., salts are filteredout, and the filtrate is evaporated to dryness. The residue ischromatographed on silica gel (mobile solvent: ethylacetate/ethanol=15/1).

[0413] Yield: 19.46 g (79% of theory) of a waxy solid

[0414] Elementary analysis:

[0415] Cld: C, 57.32; H, 7.38; N, 7.43 Na 2.43 Br 8.47

[0416] Fnd: C, 57.22; H, 7.51; N, 7.27 Na 2.33 Br 8.29

[0417] e)10-[4-Carboxy-2-oxo-1-hydroxymethyl-3-azabutyl]-1,4,7-tris(tert-butoxycarbonylmethyl)-1,4,7,10-tetraazacyclododecane(Sodium Bromide Complex)

[0418] 3 g of palladium catalyst (10% Pd/C) is added to 19 g (20.15mmol) of the title compound of Example 4d) in 300 ml of isopropanol andhydrogenated overnight at room temperature. Catalyst is filtered out,the filtrate is evaporated to dryness in a vacuum, and the residuerecrystallizes from acetone.

[0419] Yield: 13.06 g (85% of theory) of a colorless, crystalline powder

[0420] Elementary analysis:

[0421] Cld: C, 48.82; H, 7.53; N, 9.18 Na 3.00 Br 10.49

[0422] Fnd: C, 48.71; H, 7.68; N, 9.03 Na 2.81 Br 10.23

[0423] f)10[4-(Benzyloxycarbonyl)-1-(hydroxymethyl)-2-oxo-3-azabutyl]-1,4,7-tris(tert-butoxy-carbonylmethyl)-1,4,7,10-tetraazacyclododecane

[0424] 3.42 g (20 mmol) of benzyl bromide is added to 13 g (17.04 mmol)of the title compound of Example 4e) and 6.11 g (18.75 mmol) ofanhydrous cesium carbonate in 70 ml of dimethylformamide, and it isstirred overnight at 50° C. It is cooled to 0° C., and 700 ml of wateris added. Then, it is extracted twice with 300 ml of methylene chlorideeach. The combined organic phases are washed twice with water, dried onmagnesium sulfate and evaporated to dryness in a vacuum. The residue ischromatographed on silica gel (mobile solvent: ethyl acetate/ethanol).

[0425] Yield: 9.97 g (78% of theory) of a colorless, viscous oil

[0426] Elementary analysis:

[0427] Cld: C, 60.86; H, 8.47; N, 9.34

[0428] Fnd: C, 60.95; H, 8.61; N, 9.21

[0429] g) 10-[4-(Benzyloxycarbonyl)-1-(2,5,8,11,14,17,20-heptaoxa-heneicosanoyl) -2-oxo-3-azabutyl-1,4,7-tris(tert-butoxycarbonylmethyl) -1,4,7, 10-tetraazacyclododecane

[0430] 9.7 g (12.93 mmol) of the title compound of Example 4f) isdissolved in 50 ml of THF, and 0.43 g (14.22 mmol) of sodium hydride(80% in paraffin) is added at −10° C. It is stirred for 30 minutes at 0°C. Then, 11.65 g (25.86 mmol) of the title compound of Example 4a) and3.46 g (25.86 mmol) of lithium iodide F are added. It is stirred for 24hours at room temperature. 3 ml of water is carefully added and thenevaporated to dryness. The residue is chromatographed on silica gel(mobile solvent: chloroform/methanol=10:1).

[0431] Yield: 12.1 g (91% of theory) of a vitreous solid

[0432] Elementary analysis:

[0433] Cld: C, 59.57; H, 8.72; N, 6.81

[0434] Fnd: C, 59.65; H, 8.91; N, 6.62

[0435] h)10-(1-(2-8,11,14,17,20-Heptaoxa-heneicosanoyl)-2-oxo-3-aza-4-(carboxy)-butyl)-1,4,7-tris(tert-butoxycarbonylmethyl)-1,4,7,10-tetraazacyclododecane

[0436] 12 g (11.67 mmol) of the title compound of Example 4g) isdissolved in 300 ml of isopropanol and 2 g of palladium catalyst (10%Pd/C) is added. It is hydrogenated overnight at room temperature.Catalyst is filtered out, and the filtrate is evaporated to dryness. Theresidue recrystallizes from acetone/diisopropyl ether.

[0437] Yield: 10.18 g (93% of theory) of a waxy solid

[0438] Elementary analysis:

[0439] Cld: C, 56.33; H, 8.92; N, 7.46

[0440] Fnd: C, 56.20; H, 9.03; N, 7.35

[0441] i) 24-mer Gd Complex of N-(5-DO3A-yl-4-oxo-3-aza-7,10,13,16,19,22₁25-heptaoxa-hexacosanoyl)-cascade Polyamide Based onN,N,N′,N′,N″,N″-hexakis[2-(trilysylamino)-ethyl]-trimesic Acid Triamide

[0442] 6.0 g (1 mmol) of the 24-mer-benzyloxycarbonylamine described inExample 1d) is dissolved in glacial acetic acid and mixed with 33%hydrogen bromide in glacial acetic acid while being stirred. After 3hours, the incipient precipitation is completed with diethyl ether, the24-amine-hydrobromide produced is washed with ether and dried in avacuum. 45.03 g (48 mmol) of the acid described in Example 4h) above isdissolved in DMF, mixed with 7.35 g (48 mmol) of 1-hydroxybenzotriazole,with 15.41 g (48 mmol) of TBTU (Peboc Limited, UK) and with 49.3 ml (288mmol) of N-ethyldiisopropylamine and stirred for 20 minutes at roomtemperature. This solution is then mixed with the above described (1mmol) 24-amine hydrobromide and stirred for 4 days at room temperature.The solution is concentrated by evaporation in a vacuum, the remainingoil is cooled in an ice bath and mixed with trifluoroacetic acid,stirred overnight at room temperature and then precipitated with diethylether. The precipitate is dried in a vacuum, taken up in water, set atpH 3 with diluted hydrochloric acid, mixed with 8.70 g (24 mmol) ofGd₂O₃, stirred for 4 hours at 80° C., set at pH 7 after cooling, and aYM3 AMICON® ultrafiltration membrane is used to remove low-molecularportions, and the retentate is ultimately membrane-filtered andfreeze-dried.

[0443] Yield: 19.6 g (73.3% of theory)

[0444] H₂O content (Karl-Fischer): 8.3%

[0445] Gd determination (AAS): 14.0%

[0446] Elementary analysis (relative to anhydrous substance):

[0447] Cld: C, 43.94; H, 6.38; N, 9.43 Gd 15.39

[0448] Fnd: C, 44.27; H, 6.22; N, 9.29 Gd 15.09

EXAMPLE 5

[0449] a) 1,7-Bis(trifluoroacetyl)-1,4,7-triazaheptane

[0450] 113.3 g (790 mmol) of trifluoroacetic acid ethyl ester is addedin drops to a solution consisting of 41.14 g (390 mmol) of1,4,7-triazaheptane in 350 ml of tetrahydrofuran at 80° C. and undernitrogen. It is allowed to stir overnight at room temperature,concentrated by evaporation in a vacuum. The remaining oil iscrystallized from hexane.

[0451] Yield: 115 g (99.9% of theory)

[0452] Melting point: 68-70° C.

[0453] Elementary analysis:

[0454] Cld: C, 32.55; H, 3.76 F 38.62; N, 14.24

[0455] Fnd: C, 32.63; H, 3.75 F 38.38; N, 14.19

[0456] b)1,7-Bis(trifluoroacetyl)-4-benzyloxycarbonyl-1,4,7-triazaheptane

[0457] 14.75 g (50 mmol) of the trifluoroacetyl compound produced underExample 5a) as well as 8.3 ml (60 mmol) of triethylamine are dissolvedin 120 ml of dichloromethane and cooled to 0° C. While being stirred,7.5 ml (53 mmol) of benzyl chloroformate (97%), dissolved in 20 ml ofdichloromethane, is now added in drops. It is allowed to stir overnightat room temperature, the salts are extracted with distilled water, thedichloromethane solution is dried on sodium sulfate, evaporated todryness in a vacuum, and the residue is crystallized from ether/hexane.

[0458] Yield: 18.40 g (85.7% of theory)

[0459] Melting point: 131-132° C.

[0460] Elementary analysis:

[0461] Cld: C, 44.76; H, 3.99 F 26.55; N, 9.79

[0462] Fnd: C, 44.87; H, 4.03 F 26.62; N, 9.61

[0463] c) 3,9-Bis(tert-butoxycarbonylmethyl)-6-benzyloxycarbonyl-3,6,9-triazaundecanedicarboxylicacid-di-tert-butyl Ester

[0464] 4.29 g (10 mmol) of the trifluoroacetyl derivative produced underExample 5b) is dissolved in 30 ml of ethanol and mixed with 800 mg (20mmol) of sodium hydroxide solution in 10 ml of distilled water. It isstirred for 3 hours at room temperature, evaporated to dryness in avacuum at 40° C. bath temperature, residual water is removed byazeotropic distillation with isopropanol and taken up in 30 ml ofdimethylformamide. 6.9 g (50 mmol) of potassium carbonate as well as 9.7g (50 mmol) of bromoacetic acid-tert-butyl ester are then added to it,and the 4-benzyloxycarbonyl-1,4,7-triazaheptane is alkylated at roomtemperature overnight. The dimethylformamide is then drawn off in an oilpump vacuum, the residue is dispersed between water and dichloromethane,the organic solution is dried on sodium sulfate, evaporated to drynessin a vacuum, and the residue is purified by chromatography on silicagel. The title compound is eluted with ethyl acetate/hexane. It isobtained as foam.

[0465] Yield: 6.49 g (93.6% of theory)

[0466] Elementary analysis:

[0467] Cld: C, 62.32; H, 8.57; N, 6.06

[0468] Fnd: C, 62.41; H, 8.66; N, 6.01

[0469] d) 3,9-Bis(tert-butoxycarbonylmethyl)-3,6,9-triazaundecanedicarboxylicacid-di-tert-butyl Ester

[0470] 3.5 g (5 mmol) of the compound produced under Example 5c) isdissolved in 100 ml of ethanol, mixed with 200 mg of Pearlman's catalyst(Pd 20% on activated carbon) and hydrogenated until the calculatedamount of hydrogen is taken up. Catalyst is suctioned off and evaporatedto dryness in a vacuum. The title compound is obtained as white foam.

[0471] Yield: 2.80 g (99.9% of theory)

[0472] Elementary analysis:

[0473] Cld: C, 60.08; H, 9.54; N, 7.51

[0474] Fnd: C, 60.02; H, 9.62; N, 7.56

[0475] e) 3,9-Bis(tert-butoxycarbonylmethyl)-6-[1-(ethoxycarbonyl)-ethyl]-3,6,9-triazaundecanedioic acid-di-tert-butylEster

[0476] 5.60 g (10 mmol) of the amino compound produced under Example 5d)is dissolved in 30 ml of dimethylformamide. 1.66 g (12 mmol) ofpotassium carbonate as well as 2.17 g (12 mmol) of 2-bromopropionic acidethyl ester are then added to it at room temperature, and it is stirredovernight. It is then poured on ice water, extracted with ethyl acetate,the organic solution is dried on sodium sulfate, evaporated to drynessin a vacuum, and the title compound is obtained by chromatography onsilica gel. A mixture of ethyl acetate/hexane is used as eluant.

[0477] Yield: 4.18 g (63.4% of theory)

[0478] Elementary analysis:

[0479] Cld: C, 60.07; H, 9.32; N, 6.37

[0480] Fnd: C, 60.18; H, 9.40; N, 6.31

[0481] f)3,9-Bis(tert-butoxycarbonylmethyl)-6-[1-(carboxy)-ethyl]-3,6,9-triazaundecanedioicacid-di-tert-butyl Ester

[0482] 6.60 g (10 mmol) of the compound produced under Example 5e) isdissolved in 50 ml of ethanol. The solution of 400 mg (10 mmol) ofsodium hydroxide in 5 ml of distilled water is then added to it andstirred for 3 hours at 50° C. According to the thin-layer chromatogram,the saponification is quantitative. It is evaporated to dryness in avacuum, traces of water are removed by codistillation with ethanol, andthe residue is dried at 40° C. in a vacuum. The title compound isobtained-as white powder. The remaining white residue is dissolved in 80ml of wet ethanol (9:1) and mixed with the solution of 535 mg (10 mmol)of ammonium chloride in 10 ml of distilled water while being stirred. Itis evaporated to dryness in a vacuum, the soluble portions in butanolare taken up and again evaporated to dryness in a vacuum. The residue isextracted with toluene. The organic solution is evaporated to dryness ina vacuum, and the title compound is obtained as foam.

[0483] Yield: 5.35 g (84.7% of theory)

[0484] Elementary analysis:

[0485] Cld: C, 58.93; H, 9.09; N, 6.65

[0486] Fnd: C, 59.01; H, 9.16; N, 6.60

[0487] g) 24-merN-{N,N-bis[2-(N,N-bis(carboxymethyl))-aminoethyl]-alanyl}-cascade-polyamidebased on N,N,N′,N′,N″,N″-hexakis[2-(trilysylamino)-ethyl]-trimesic acidtriamide, sodium salt

[0488] 6.0 g (1 mmol) of the poly-benzyloxycarbonylamine described inExample 1d) is dissolved in glacial acetic acid and mixed with 33%hydrogen bromide in glacial acetic acid while being stirred. After 3hours, the incipient precipitation is completed with diethyl ether, the24-amine-hydrobromide produced is washed with ether and dried in avacuum.

[0489] 30.33 g (48 mmol) of the acid described in Example 5f) above isdissolved in DMF, mixed with 7.35 g (48 mmol) of 1-hydroxybenzotriazole,with 15.41 g (48 mmol) of TBTU (Peboc Limited, UK) and with 49.3 ml (288mmol) of N-ethyldiisopropylamine, and it is stirred for 20 minutes atroom temperature. This solution is then mixed with the (1 mmol)24-amine-hydrobromide described above, and it is stirred for 4 days atroom temperature. The solution is concentrated by evaporation in avacuum, the remaining oil is cooled in an ice bath and mixed withtrifluoroacetic acid, stirred overnight at room temperature and thenprecipitated with diethyl ether. The precipitate is dried in a vacuum,taken up in water, set at pH 7, a YM3 Amicon® ultrafiltration membraneis used to remove low-molecular portions, and the retentate isultimately membrane-filtered and freeze-dried.

[0490] Yield: 11.0 g (86.3% of theory)

[0491] H₂O content (Karl-Fischer): 8.2%

[0492] Elementary analysis (relative to anhydrous substance):

[0493] Cld: C, 42.87; H, 5.41; N, 11.96 Na 12.08

[0494] Fnd: C, 42.78; H, 5.66; N, 12.11 Na 11.89

[0495] h) 24-mer-Gd Complex ofN-{N,N-bis[2-(N,N-bis(carboxymethyl))-aminoethyl]-alanyl}-cascadePolyamide Based onN,N,N′,N′,N″,N″-hexakis[2-(trilysylamino)-ethyl]-trimesic Acid Triamide,Sodium Salt

[0496] 8.13 g (0.5 mmol) of the complexing agent acid described inExample 5g) above is set at pH 3 in water with diluted hydrochloricacid, mixed with 2.17 g (6 mmol) of Gd₂O₃ stirred for 30 minutes at 80°C., set at pH 7 after cooling and desalinated with a YM3 AMICON°ultrafiltration membrane. The retentate is ultimately membrane-filteredand freeze-dried.

[0497] Yield: 8.0 g (90.5% of theory)

[0498] H₂O content (Karl-Fischer): 7.5%

[0499] Gd determination (AAS): 21.0%

[0500] Elementary analysis (relative to anhydrous substance):

[0501] Cld: C, 35.93; H, 4.38; N, 10.03 Gd 23.09 Na 3.38

[0502] Fnd: C, 35.71; H, 4.65; N, 9.88 Gd 22.84 Na 3.50

EXAMPLE 6

[0503] a)3,9-Bis(tert-butoxycarbonylmethyl)-6-benzyloxycarbonylmethyl-3₁6,9-triazaundecanedioicacid-di-tert-butyl Ester

[0504] 5.60 g (10 mmol) of the amino compound produced under Example 5d)is dissolved in 30 ml of dimethylformamide. 1.66 g (12 mmol) ofpotassium carbonate as well as 2.58 g (12 mmol) of bromoacetic acidbenzyl ester are then added to it and stirred overnight. It is thenpoured onto ice water, extracted with ethyl acetate, the organicsolution is dried on sodium sulfate, evaporated to dryness in a vacuum,and the title compound is obtained by chromatography on silica gel. Amixture of ethyl acetate/hexane is used as eluant.

[0505] Yield: 6.32 g (89.3% of theory)

[0506] Elementary analysis:

[0507] Cld: C, 64.65; H, 9.00; N, 5.95

[0508] Fnd: C, 64.62; H, 9.07; N, 5.90

[0509] b) 3,9-Bis(tert-butoxycarbonylmethyl)-6-carboxymethyl-3,6,9-triazaundecanedioicacid-di-tert-butyl Ester

[0510] 7.08 g (10 mmol) of the benzyl ester produced under 6a) isdissolved in 100 ml of ethanol and mixed with 0.4 g of Pearlman'scatalyst (Pd 20%, C). It is hydrogenated until 224 ml of hydrogen istaken up, catalyst is suctioned out, rewashed well with ethanol, and thesolution is evaporated to dryness in a vacuum. The product is obtainedas foam, which crystallizes from ether/hexane.

[0511] Yield: 6.87 g (97.3% of theory)

[0512] Melting point: 73-75° C.

[0513] Elementary analysis:

[0514] Cld: C, 57.85; H, 9.00; N, 5.95

[0515] Fnd: C, 57.91; H, 9.11; N, 6.01

[0516] c) 32-merN-{N,N-Bis[2-(N,N-bis(carboxymethyl))-aminoethyl]-glycyl}-cascade-polyamideBased on the 32-mer Amine Described in Example 3c), Sodium Salt

[0517] 8.35 g (1 mmol) of the 32-mer-benzyloxycarbonylamine described inExample 3c) is dissolved in glacial acetic acid and mixed with 33%hydrogen bromide in glacial acetic acid while being stirred. After 3hours, the incipient precipitation is completed with diethyl ether, the32-amine-hydrobromide produced is washed with ether and dried in avacuum.

[0518] 39.5 g (64 mmol) of the acid described in Example 6b) above isdissolved in DMF, mixed with 9.8 g (64 mmol) of 1-hydroxybenzotriazole,with 20.5 g (64 mmol) of TBTU (Peboc Limited, UK) and with 65.7 ml (384mmol) of N-ethyldiisopropylamine, and it is stirred for 20 minutes atroom temperature. This solution is then mixed with the (1 mmol)32-amine-hydrobromide described above, and it is stirred for 4 days atroom temperature. The solution is concentrated by evaporation in avacuum, the remaining oil is cooled in an ice bath and mixed withtrifluoroacetic acid, stirred overnight at room temperature and thenprecipitated with diethyl ether. The precipitate is dried in a vacuum,taken up in water, set at pH 7, a YM3 Amicon® ultrafiltration membraneis used to remove low-molecular portions, and the retentate isultimately membrane-filtered and freeze-dried.

[0519] Yield: 15.7 g (78.6% of theory)

[0520] H₂O content (Karl-Fischer): 9.0%

[0521] Elementary analysis (relative to anhydrous substance):

[0522] Cld: C, 41.77; H, 5.24; N, 12.33 Na 12.14

[0523] Fnd: C, 41.49; H, 5.36; N, 12.49 Na 11.93

[0524] d) 32-mer-Gd-complex of theN-{N,N-bis[2-(N,N-bis(carboxymethyl)-aminoethyl]-glycyl}-cascadePolyamide Based on the 32-mer Amine Described in Example 3c), SodiumSalt

[0525] 10.0 g (0.5 mmol) of the complexing agent acid described inExample 6c) above is set at pH 3 in water with diluted hydrochloricacid, mixed with 2.89 g (8 mmol) of Gd₂O₃, stirred for 30 minutes at 80°C., set at pH 7 after cooling and desalinated with a YM3 AMICON®ultrafiltration membrane. The retentate is ultimately membrane-filteredand freeze-dried.

[0526] Yield: 10.9 g (90.9% of theory)

[0527] H₂O content (Karl-Fischer): 9.5%

[0528] Gd determination (AAS): 20.9%

[0529] Elementary analysis (relative to anhydrous substance):

[0530] Cld: C, 34.98; H, 4.24; N, 10.33 Gd 23.19 Na 3.39

[0531] Fnd: C, 35.20; H, 4.08; N, 10.46 Gd 22.89 Na 3.60

[0532] Example for an In vivo Comparison with an Extracellular ContrastMedium

[0533] The suitability of the compound described in Example 1k) asblood-pool-agent is shown in the following test.

[0534] As test animals, five male (Schering-SPF) rats that are 300-350 gin weight are used. Before the test, the abdomen is opened, theintestines are shifted and then the renal vessels (arterial+venous) ofboth sides are ligated through the rear peritoneum with a surgicalneedle. Then, the abdominal cavity is closed again. 0.3 ml (respectively50 mmol/L) of the following contrast medium solution per animal is thenadministered intravenously: mixture of 1 part each of the compound ofExample 1k), named compound 1 below, and the dysprosium complex of10-(1-hydroxymethyl-2,3-dihydroxypropyl)-1,4,7-tris(carboxymethyl)-1,4,7,10-tetraazacyclododecane,produced analogously to the instructions in European Patent ApplicationEP 448 191, named compound 2 below. Blood samples are taken with acatheter in the common carotid artery at the following times: 15, 30,45, 60, 90 seconds, 3, 5, 10, 15 minutes p.i. In the blood samplesobtained, the concentrations of gadolinium (Gd) and dysprosium (Dy) aremeasured with the aid of atomic emission spectrometry (ICP-AES) in eachcase in a parallel manner. The portion of the injected contrast mediumof compound 1 (Gd) and compound 2 (Dy, comparison substance), remainingin the blood space, can be compared in the same animals by the differentmarking. Since a renal excretion is not possible, the decrease of theblood concentration can be attributed only to a distribution in theblood spaces and to the diffusion in the interstitial tissue.

[0535] Results:

[0536] The diffusion of compound 1 in the interstitium is considerablyslowed-down in comparison to an extracellular contrast medium compound 2(see FIG. 1).

[0537] The extracellular contrast medium (compound 2) diffuses quicklyinto the interstitial spaces of the body, so that as early as after 3-5minutes p.i., an equilibrium is reached (displayed by constant bloodlevel). In contrast to this, not only are constantly higher bloodconcentrations measured with the cascade polymer (compound 1) (referenceto smaller volume of distribution), in addition no equilibrium isreached over the entire examination period of 15 minutes (reference todiffusion into interstitial tissue proceeding only very slowly). Thismeans that compound 1 behaves as a blood-pool contrast medium.

[0538]FIG. 1

[0539] Measured blood concentrations of Gd (compound 1) and Dy (compound2) in rats (n=5) with ligated renal vessels

[0540] [Key:]

[0541] Zeit (min. p.i.]=Time [minutes p.i.]

[0542] Example of an MR Angiography on Rabbits

[0543] The compound cited under Example 1k was studied on rabbits (CH.R. Kisslegg, ≈4 kg of body weight) in an MR angiography experiment(Ganzkörper [Whole-Body] MRT System Siemens Vision, 1.5 tesla, FISP 3D;TR: 400 ms; TE 15 ms; flip angle: 450; coronal).

[0544] In the precontrast picture (see photo), only one to two majorvessels are visible (e.g., abdominal aorta) in relatively poor contrast(signal intensity SI of these vessels against the background). Afteri.v. administration of 50 μmol of Gd/kg of body weight of the compounddescribed in Example 1k, a marked increase in contrast (SI of thevessels/SI of the background) and a wide variety of minor blood vesselsand capillaries (e.g., A. and V. femoralis, A. and V. mesentericacaudalis, A. and V. renalis, A. and V. subrenalis, etc.), which couldnot be detected before the administration of contrast medium, arevisible.

[0545] Example of Lymph Node Accumulation in Guinea Pigs

[0546] The compound according to the invention that is cited underExample 1k was studied 30 minutes to 24 hours after subcutaneousadministration (10 μmol of gadolinium/kg of body weight, hind paw s.c.)in stimulated guinea pigs (complete Freund's adjunct; in each case 0.1ml i.m. in the right and left upper and lower legs; 2 weeks beforeadministration of the test substances) to determine its lymph nodeaccumulation in three successive lymph node stations (popliteal,inguinal, iliac). In this case, the results listed below (determinationof gadolinium accumulation with the aid of ICP-AES) were obtained:Gadolinium Accumulation in Three Successive Time of Lymph Node Stations[μmol/l] Lymph Node [% of Dose/g of Tissue] Removal Popliteal InguinalIliac Ratio 30 min p.i 921 μmol/l 387 μmol/l 215 μmol/l 10:4.2:2.3 20.1%8.5% 4.7% 90 min p.i. 659 μmol/l 120 μmol/l 68 μmol/l 10:1.8:1.0 14.4%2.6% 1.5% 4 h p.i. 176 μmol/l 79 μmol/l 47 μmol/l 10:4.5:2.7 3.9% 1.7%1.0% 24 h p.i. 62 μmol/l 13 μmol/l 28 μmol/l 10:2.1:4.5 1.4% 0.3% 0.6%

[0547] The preceding examples can be repeated with similar success bysubstituting the generically or specifically described reactants and/oroperating conditions of this invention for those used in the precedingexamples.

[0548] From the foregoing description, one skilled in the art can easilyascertain the essential characteristics of this invention, and withoutdeparting from the spirit and scope thereof, can make various changesand modifications of the invention to adapt it to various usages andconditions.

1. A cascade polymer complex comprising a) a complexing ligand ofgeneral formula I A—{X—[Y—(Z—<W—K_(W)>_(Z))_(y)]_(x)}_(a)  (I), in whichA stands for a nitrogen-containing cascade nucleus of base multiplicitya, X and Y, independently of one another, stand for a direct bond or acascade reproduction unit of reproduction multiplicity x or y, Z and W,independently of one another, stand for a cascade reproduction unit ofreproduction multiplicity z or w, K stands for the radical of acomplexing agent, a stands for numbers 2 to 12, x, y, z and w,independently of one another, stand for numbers 1 to 4, f provided thatat least two cascade reproduction units are different and that for theproduct of the multiplicities, 16≦a·x·y·z·w≦64 holds true, b) at least16 ions of an element of atomic numbers 20 to 29, 39, 42, 44 or 57.-83,c) optionally one or more cations of inorganic and/or organic bases,amino acids or amino acid amides and d) optionally, one or more acylatedterminal amino grou
 2. A cascade polymer complex according to claim 1wherein A means a nitrogen atom,

in which m and n independently stand for numbers 1 to 10, p stands fornumbers 0 to 10, U¹ stands f or Q¹ or E, U² stands for Q² or E with Emeaning the group

whereby o stands for numbers 1 to 6, Q¹ stands for a hydrogen atom orand Q² stands for a direct bond, M stands for a C₁-C₁₀ alkylene chainwhich optionally is interrupted by 1 to 3 oxygen atoms and/or optionallyis substituted with 1 to 2 oxo groups, R^(o) stands for a branched orunbranched C₁-C₁₀ alkyl radical, a nitro, amino, carboxylic acid groupor for

whereby the number of Q² elements corresponds to base multiplicity a. 3.A cascade polymer complex according to claim 1, wherein cascadereproduction units X, Y, Z and W, independently of one another, standfor E,

in which U¹ stands for Q¹ or E, U² stands for Q² or E with E meaning thegroup

whereby o stands for numbers 1 to 6, Q¹ stands for a hydrogen atom orQ², Q² stands for a direct bond, U³ stands for a C₁-C₂₀ alkylene chain,which optionally is interrupted by 1 to 10 oxygen atoms and/or 1 to2-N(CO)_(q)—R² radicals, 1 to 2 phenylene radicals and/or 1 to 2phenylenoxy radicals and/or optionally is substituted by 1 to 2 oxo,thioxo, carboxy, C₁-Cs alkylcarboxy, C₁-C₅ alkoxy, hydroxy, or C₁-C₅alkyl groups, whereby q stands for numbers 0 or 1 R² stands for ahydrogen atom, or a methyl or an ethyl radical, which optionally issubstituted with 1-2 hydroxy or 1 carboxy group(s), L stands for ahydrogen atom or the group

V stands for methine group

if at the same time U⁴ means a direct bond or group M and U⁵ has one ofthe meanings of U³ or V stands for group

if at the same time T and U¹ are identical and mean the direct bond orgroup M, and M stands for a C₁-C₁₀ alkylene chain which optionally isinterrupted by 1 to 3 oxygen atoms and/or optionally is substituted with1 to 2 oxo groups.
 4. A cascade polymer complex according to claim 1,wherein complexing agent radical K bound to the terminal nitrogen atomsof the last generation of reproduction unit W stands for a radical ofgeneral formulas IA or IB

in which R¹, independently of one another, stand for a hydrogen atom ora metal ion equivalent of atomic numbers 20-29, 39, 42-44 or 57-83, R²stands for a hydrogen atom, or a methyl or an ethyl radical, whichoptionally is substituted with 1-2 hydroxy or 1 carboxy group(s), R³stands for a

group, R⁴ stands for a straight-chain, branched, saturated orunsaturated C₂-C₃₀ alkyl chain, which optionally is interrupted by 1-10oxygen atoms, 1 phenylene group, or phenylenoxy group and/or optionallysubstituted by 1-hydroxy, 1-3 carboxy, or 1-phenyl group(s), R⁵ standsfor a hydrogen atom or for R⁴, U⁶ stands for a straight-chain, branched,saturated or unsaturated C₁-C₂₀ alkylene group optionally containing 1-5imino, 1-3 phenylene, 1-3 phenylenoxy, 1-3 phenylenimino, 1-5 amide, 1-2hydrazide, 1-5 carbonyl, 1-5 ethylenoxy, 1 urea, 1 thiourea, 1-2carboxyalkylimino, 1-2 ester groups, and/or 1-10 oxygen, 1-5 sulfurand/or 1-5 nitrogen atom(s) and/or optionally substituted by 1-5hydroxy, 1-2 mercapto, 1-5 oxo, 1-5 thioxo, 1-3 carboxy, 1-5carboxyalkyl, 1-5 ester and/or 1-3 amino group(s), whereby the phenylenegroups that are optionally contained can be substituted by 1-2 carboxy,1-2 sulfo or 1-2 hydroxy groups, T stands for a —CO-α, —NHCO-α or—NHCS-α group and α stands for the bonding site to the terminal nitrogenatoms of the last generation of reproduction unit W.
 5. A cascadepolymer complex according to claim 4, wherein the C₁-C₂₀ alkylene chainthat stands for U¹ contains the groups —CH₂, —CH₂NHCO, —NHCOCH₂O,—NHCOCH₂OC₆H₄, —N(CH₂CO₂H), —NHCOCH₂C₆H₄, —NHCSNHC₆H₄, —CH₂OC₆H₄, or—CH₂CH₂O and/or is substituted by groups —COOH, or —CH₂COOH.
 6. Acascade polymer complex according to claim 4, wherein U⁶ stands for a—CH₂, —CH₂CH₂, —CH₂CH₂CH₂, —C₆H₄, —C₆H₁₀, —CH₂C₆H₅,—CH₂NHCOCH₂CH(CH₂CO₂H)—C₆H₄; —CH₂NHCOCH₂OCH₂, or —CH₂NHCOCH₂C₆H₄ group.7. A cascade polymer complex according to claim 3, wherein radical U³contained in cascade reproduction units X, Y, Z and W stands for —CO—,—COCH₂OCH₂CO—, —COCH₂—, —CH₂CH₂—, —CONHC₆H₄—, —COCH₂CH₂CO—,—COCH₂—CH₂CH₂CO—, or —COCH₂CH₂CH₂CH₂CO—, radical U⁴ stands for a directbond, or for —CH₂CO—, radical U⁵ stands for a direct bond, —(CH₂)₄—,—CH₂CO—, —CH(COOH)—, CH₂OCH₂CH₂—, —CH₂C₆H₄—, or CH₂—C₆H₄OCH₂CH₂—,radical E stands for a group


8. A cascade polymer complex according to claim 3, wherein cascadereproduction units X, Y, Z and W, independently of one another, standfor —CH₂CH₂NH—; —CH₂CH₂N<; —COCH(NH—)(CH₂)₄NH—; —COCH(N<)(CH₂)₄N<;—COCH₂OCH₂CON(CH₂CH₂NH—)₂; —COCH₂OCH₂CON(CH₂CH₂N<)₂;—COCH₂N(CH₂CH₂NH—)₂; —COCH₂N(CH₂CH₂N<)₂; —COCH₂NH—; —COCH₂N<;—COCH₂CH₂CON(CH₂CH₂NH—)₂; —COCH₂CH₂CON(CH₂CH₂N<)₂;—COCH₂OCH₂CONH—C₆H₄—CH[CH₂CON(CH₂CH₂NH—)₂]₂;—COCH₂OCH₂CONH—C₆H₄—CH[CH₂CON(CH₂CH₂N<)₂]₂;—COCH₂CH₂CO—NH—C₆H₄—CH[CH₂CON(CH₂CH₂NH—)₂]₂;—COCH₂CH₂CO—NH—C₆H₄—CH[CH₂CON(CH₂CH₂N<)₂]₂;—CONH—C₆H₄—CH[CH₂CON(CH₂CH₂NH—)₂]₂; —CONH—C₆H₄—CH[CH₂CON(CH₂CH₂N<)₂]₂;—COCH(NH—)CH(COOH)NH—, —COCH(N<)CH(COOH)N<;


9. A cascade polymer complex according to claim 2, wherein m stands fornumbers 1-3, n stands for numbers 1-3, o stands for number 1, p standsfor numbers 0-3, M stands for a —CH₂, —CO or —CH₂CO group and R^(o)stands for a —CH₂NU¹U², CH₃ or NO₂ group.
 10. A pharmaceutical agentcomprising at least one cascade polymer complex according to claim 1,and a pharmaceutically acceptable carrier.
 11. A method of NMRdiagnosis, e.g., imaging or diagnostic radiology, e.g., CT imaging,comprising administering at least one polymer complex according toclaim
 1. 12. A method for differentiating benign and malignant tumors inregions of the body without blood-brain barriers comprising imaging suchtumors by administering a cascade polymer complex according to claim 1.13. Process for the production of cascade polymer complexes according toclaim 1, wherein compounds of general formula I′A—{X—[Y—(Z—<W-β_(W)>_(z))_(y)]_(x) }a  (I′), in which A stands for anitrogen-containing cascade nucleus of base multiplicity a, X and Y,independently of one another, stand for a direct bond or a cascadereproduction unit of reproduction multiplicity x or y, Z and W,independently of one another, stand for a cascade reproduction unit ofreproduction multiplicity z or w, a stands for numbers 2 to 12, x, y, zand w, independently of one another, stand for numbers 1 to 4 and βstands for the bonding site of the terminal NH groups of the lastgeneration, of reproduction unit W, provided that at least tworeproduction units are different and that for the product of themultiplicities, 16≦a·x·y·z·w≦64 holds true, are reacted with a complexof complexing agent K¹ of general formula I′A or I′B

whereby R^(1′), independently of one another, stand for a hydrogen atom,a metal ion equivalent of atomic numbers 20-29, 39, 42-44, or 57-83 oran acid protective group, R² stands for a hydrogen atom, a methyl-or anethyl radical, which optionally is substituted with 1-2 hydroxy or 1carboxy group(s), R^(3′) stands for a

group, R⁴ stands for a straight-chain, branched, saturated orunsaturated C₁-C₃₀ alkyl chain, which optionally is interrupted by 1-10oxygen atoms, 1 phenylene group, 1 phenylenoxy group and/or optionallysubstituted by 1-5 hydroxy, 1-3 carboxy, 1-phenyl group(s), R⁵ standsfor a hydrogen atom or for R⁴, U⁶ stands for a straight-chain, branched,saturated or unsaturated C₁-C₂₀ alkylene group optionally containing 1-5imino, 1-3 phenylene, 1-3 phenylenoxy, 1-3 phenylenimino, 1-5 amide, 1-2hydrazide, 1-5 carbonyl, 1-5 ethylenoxy, 1 urea, 1 thiourea, 1-2carboxyalkylimino, 1-2 ester groups; 1-10 oxygen, 1-5 sulfur and/or 1-5nitrogen atom(s) and/or optionally substituted by 1-5 hydroxy, 1-2mercapto, 1-5 oxo, 1-5 thioxo, 1-3 carboxy, 1-5 carboxyalkyl, 1-5 esterand/or 1-3 amino group(s), whereby the phenylene groups that areoptionally contained can be substituted by 1-2 carboxy, 1-2 sulfo or 1-2hydroxy groups, T′ stands for a —C*O, —COOH, —N═C═O or —N═C═S group, andC*O stands for an activated carboxyl group provided that—if K′ standsfor a complex—at least two (in the case of divalent metals) or three (inthe case of trivalent metals) of substituents R¹ stand for a metal ionequivalent of the above-mentioned elements and that optionally othercarboxyl groups are present in the form of their salts with inorganicand/or organic bases, amino acids or amino acid amides, optionallypresent protective groups are cleaved, the thus obtained cascadepolymers—if K′ stands for a complexing agent—are reacted in a way knownin the art with at least one metal oxide or metal salt of an element ofatomic numbers 20-29, 39, 42, 44, or 57-83 and optionally then in thecascade polymer complexes thus obtained, acid hydrogen atoms that arestill present are completely or partially substituted by cations ofinorganic and/or organic bases, amino acids, or amino acid amides andoptionally still present free terminal amino groups are optionallyacylated—before or after the metal completing.
 14. A compound of generalformula I′A

wherein R^(1′), independently of one another, stand for a hydrogen atom,a metal ion equivalent of atomic numbers 20-29, 39, 42-44 or 57-83 or anacid protective group, R² stands for a hydrogen atom, or a methyl or anethyl radical, which optionally is substituted with 1-2 hydroxy or 1carboxy group(s), R^(3′) stands for a

group, R⁴ stands for a straight-chain, branched, saturated orunsaturated C₁-C₃₀ alkyl chain, which optionally is interrupted by 1-10oxygen atoms, 1 phenylene group, or 1 phenylenoxy group and/oroptionally is substituted by 1-5 hydroxy, 1-3 carboxy, or 1-phenylgroup(s), U⁶ stands for a straight-chain, branched, saturated orunsaturated C₁-C₂₀ alkylene group optionally containing 1-5 imino, 1-3phenylene, 1-3 phenylenoxy, 1-3 phenylenimino, 1-5 amide, 1-2 hydrazide,1-5 carbonyl, 1-5 ethylenoxy, 1 urea, 1 thiourea, 1-2 carboxyalkylimino,1-2 ester groups and/or 1-10 oxygen, 1-5 sulfur and/or 1-5 nitrogenatom(s) and/or optionally substituted by 1-5 hydroxy, 1-2 mercapto, 1-5oxo, 1-5 thioxo, 1-3 carboxy, 1-5 carboxyalkyl, 1-5 ester and/or 1-3amino group(s), wherein the phenylene groups that are optionallycontained can be substituted by 1-2 carboxy, 1-2 sulfo or 1-2 hydroxygroups, T¹ stands for a —C*O, —COOH, —N═C═O or —N═C═S group, and C*Ostands for an activated carboxyl group.
 15. Process for the productionof pharmaceutical agents according to claim 10, wherein the cascadepolymer complexes, dissolved or suspended in water or physiological saltsolution, optionally with the additives that are commonly used ingalenicals, are brought into a form suitable for enteral or parenteraladministration.